In this study, we investigated the effect of bathing with cut crude drugs on thermal preservability, water holding capacity, and smoothness of the feel. After immersion with cut crude drugs of 5min at 41°C, the forearm skin core temperature was significantly higher than after plain water bathing. Water sorption-desorption tests on the skin in vivo with cut crude drug extract for the functional assessment of the stratum corneum revealed that the GARENIAE FRUCTUS extract, all of cut crude drugs extract, and FOENICULI FRUCTUS extract are significantly superior to plain water bathing in water holding capacity.
Furthermore, an evaluation using a skin model revealed that cut crude drugs have effects significantly superior to that of plain water bathing in increasing the smoothness of the feel. The above results clarified that bathing with cut crude drugs has a stronger effect on thermal preservability and that their extract increases water holding capacity and smoothness of the feel.

To clarify a mechanism of psychologic relaxation by artificial hot spring, the effect of hot spring bathing on psychologic sweating was studied in 11 healthy subjects (1 female and 10 males, age 26±5.7 years). After lying in the supine position for 5 minutes, the subjects were asked to take a bath with plain water or artificial hot spring for 5 minutes in the sitting position. The temperature of the bath was 40°C. To prepare the artificial hot spring, sodium sulfate tablet (Tsumura & Co.) was solved in 200L of plain water. For the measurement of psychologic sweating, Perspiro (Suzuken, Co. Ltd) was used. Sensor was attached to the first finger by biphasic adhesive tape. The psychologic sweating was induced by deep respiration, mental arithmetic, hand grip, blood pressure measurement and blood sampling. There were no statistical significant differences of CV value, heart rate, blood pressures, catecholamine values and serum β endorphin levels before and after the bathing. The psychologic sweating markedly decreased after the bathing (11.5±19.6 to 1.1±2.7 for plain water bathing, 14.9±21.9 to 1.6±5.1 for artificial hot spring, N. S.).
The decrease in psychologic sweating after bathing suggests the action of psychologic relaxation by bathing.

Using BASUKURIN, an inorganic salts, its power of relieving bathers of their subjective symptom was analysized by main component analysis.
Subjects were 30 patients per each of 6 groups of disease, i. e. neuralgia, rheumatism lumbago, stiff shoulder, contusion and distorsion, with only cases of more than 2 week-suffering for the latter of 2 diseases Bathing test was performed in 400L of elevator bath added with 34g of BASUKURIN compsed mainly of sodium bicarbonate and sodium sulphate and with 23g of placebo composed mainly of granuated sugar, respectively. Both bath drugs, supplied by Tsumuar Juntendo Inc., were jasmin-odored. In some caces, 50 L-partial bath was also used. According to the double blind method, those subjects were bathed successively in BASUKURIN-bath and pracebo-one for 3 consecutive days, and asked for their answers to the enquete about the difference which they possibly felt there between. The choice of which bath was arbitrary. Bathing was taken at 40°C for 10min. The enquete comprised 17 items to which subjectively expressed answers were corresponded, which answers being evaluated 7 stepwise.
(1) For the neuralgia group, effects were observed as “physiologically improved” and/or “getting warmed”. Improvement were made mainly in pain perception disorder and joint dysfunction.
(2) For the rheumatism group, effects were observed generally as “getting warmed”, and as “feeling familiar” and/or “feeling refreshed” for the case of skin hypersensitiveness.
(3) For the lumbago group, effects were observed also as “getting warmed” frequently, and as “feeling similar like hot spring” and/or “feeling familiar” for the relief of muscle hypertonus.
(4) For the stiff shoulder group, effects were observed not only as “getting warmed” generally, but also on the dysfunction of cervico-shoulder-arm and as “feeling familiar” for the relief of muscle hypertonus,
(5) For the contusion group, effects were observed as “feeling refreshed”, “feeling kept warmed”, “feeling familiar”, “feeling affined”, etc. accompanying with the local pain, malaise, cold sensation and so on.
(6) For the distorsion group, effects were observed characteristically as “feeling familiar” and “improved circulation” accompanying with circulatory insufficiency of the lower extremities.
As mentioned above, from the viewpoint by diseases, main symptoms will be improved directly, and improvements will be expressed as in the disease itself. On the other hand, from the overall viewpoint, score of improvements will be leveled, so that “getting warmed” and “feeling warmth” will be emphasized as common factors. Improvements, however, may be ascribable to the effects of both sodium bicarbonate and sodium sulphate as main ingredients of BASUKURIN.

The warming effect of natrium-hydrogen carbonate-sulfate springs was evaluated experimentally using rabbits with Na₂SO₄·NaHCO₃ by means of medical mass spectrometry.
No changes were seen on the subcutaneous tissue pO₂ and pCO₂.
Regional subcutaneous tissue perfusion volume was calculated at 22.57±2.08ml/100g/min (SD=4.45, n=20, p<0.05) with Na₂SO₄·NaHCO₃ bathings which was comparable to that of tap water bathing 20.85±3.56ml/100g/min, (SD=6.71, n=16, p<0.05).
Our preliminary data of the following study indicate that the effect of warming with Na₂SO₄·NaHCO₃ bathings is due possibly to some cellular changes in the connective tissue by mild stimulation of bathing, leading to amelioration of defense mechanism in the body; the study will be reported shortly.

Promethazine-HCl was used to suppress histamine production in the skin by Na₂SO₄·NaHCO₃ bathing, confirming the previous data that the small amount of histamine released as a chemical mediator may have caused the warming effect, as observed in type I allergic reaction.
The skin histamine contents after serial bathings with Na₂SO₄·NaHCO₃ under medication of Promethazine-HCl for 3 weeks were significantly reduced compared with that of tap water (p<0.05).
The skin histamine produced by physical stimulation of Na₂SO₄·NaHCO₃ bathing was suppressed with H₁-blocker (Promethazine), verifying that the warming effect with Na₂SO₄·NaHCO₃ bathing was caused by histamine released as a chemical mediator, as observed in type I allergic reaction.

We investigated the effects of bathing with bath preparation (sodium sulfate, sodium chloride, 30g/200l) on the thermal preservability in healthy volunteers. We also investigated these effects on the antioxidative defense system in patients with vibration syndrome (VS). In these investigations, we measured the activities of erythrocyte superoxide dismutase (SOD).
After immersion at 41°C for 5min, forearm skin temperature, photoplethysmograph, and transepidermal water loss increased significantly as compared with those after bathing in a plain water.
After bathing for 4 weeks at around 40°C for 10min, activities of erythrocyte SOD increased significantly.
These data indicate that bathing with the bath preparation has a stronger effect on thermal preservability in healthy volunteers and activation of the antioxidative defense system in patients with vibration syndrome due to a significant increase in activities of erythrocyte SOD.

The effects of single bathing of the artificial mineral spring (Basukurin: Tsumura Juntendo Inc. Japan), equivalent mixture of sodium sulfate and sodium bicarbonate, were studied in 13 normal and 22 hypertensive subjects comparing with natural simple hot spring (Kirisima spa).
Blood pressure (BP: automatic sphygmomanometer), heart rate (HR), cardiac output (CO: earpiece type dye-dilution densisometer), total peripheral resistance (TPR: mean BP/cardiac index), forehead deep body temperature (DBT: Core Temp CTM 204) plasma renin activity (PRA: RIA by Habar's method), plasma norepinephrine (NE) and blood gas partial pressure (pO₂ and pCO₂) and pH were measured before and after bathing. Mineral concentration of simple hot spring and Basukurin bath (120g powder/360l simple hot spring) were 0.019% and 0.052%, respectively. The temperature and duration of bathing were both 41°C for 10min.
In normotensives, only systolic BP and TPR were significantly decreased 30min after the simple and Basukurin bathing by the same degree. HR was significantly increased throughout 30min after both bathing. CO was increased only after 10min of Basuku rin bathing. In hypertensives, systolic and diastolic BP and TPR were significantly decreased throughout 30min after simple and Basukurin bathing. The decrement in BP and TPR, however were significantly greater in Basukurin bathing. HR and CO were significantly increased after both bathing. Forehead DBT was significantly elevated after both bathing and gradually decreased throughout 30min of observation. In Basukurin bathing, although the increment in DBT was greater than simple hot spring bathing, the decrease was slower than simple hot spring bathing suggsting the protection from heat radiation by Basukurin bathing. PRA and plasma NE concentration examined in hypertensive subjects after 30min of bathing were significantly elevated only in Basukurin bathing. Although arterial gas concentration and pH were not changed after bathing, venous blood pO₂ and pH were significantly increased and pCO₂ was significantly decreased after 10min of Basukurin bathing.
These data indicates that single Basukurin bathing has more potent hypotensive effect due to vasodilation than simple hot spring. Enhanced vasodilation by Basukurin bathing is probably derived from the protection of heat radiation from the skin by the formtion of thin mineral film on the skin. Increased venous blood pO₂ and pH and decreased pCO₂ represents also the improvement of peripheral circulation assisted by vasodilation and elevated CO.

The changes of skin surface hydration state were measured in vivo to evaluate the efficacy of bath preparations and their common use raw materials, following five samples, from a view point of moisturizing effect using High Frequency Impedance Measurment (3.5MHz.) as an empirical approach previously adopted by Tagami et al.
The temparature of water immersion was 41°C and the duration was 5min. Five kinds of samples used in this survey, 15 and 30g of sodium hydrogencarbonate, bath preparations containing 85% of sodiumu hydrogen carbonate, 2% of JOJOBA OIL, and 5% of dextrin were dissolved into plain water equipped with the maintenance of water temparature at 41°C, respectively.
As the result of this examination, these five samples enhanced the hydration state of stratum corneum after immersion and the value of skin surface hydration state showed high significant difference comparing to plain water. Especially, sample A immersion (containing 2% of JOJOBA OIL; Fig. 1) showed clear cut difference to compare to plain water immersion. (P<0.01 at 30, 60, 90, and 120min, after immersion)
These data suggested that JOJOBA OIL, dextrin and sodium hydrogen carbonate can be utilized effectively as a moisturizing factor for various types of bath preparations. It was proved that JOJOBA OIL, dextrin, and sodium hydrogen carbonate as raw materials of bath preparations possess the moisturizing effect after immersion through this survey.
We suppose that these raw materials might be concerned in the quantity of secondary bound water which is necessary to retain the suppleness and smoothness of stratum corneum, and propose that High Frequency Impedance Measurement (3.5MHz) is a suitable method to evaluate the hydration state of stratum corneum after water immersion.

The warming effect of alkaline saline springs is thought to be caused by the presence of Na₂SO₄·NaHCO₃. To clarify the warming effect of alkaline saline springs, an experimental study was carried out using 5 adult rabbits for each 36-37°C bath every day for 20 minutes without anesthesia, on the assumption that cells in the skin tissue were activated to produce histamine by chemical stimulation. The chemical composition of each artificial salt bath was 4 times higher than normal. Skin histamine was measured by fluorescence analysis.
Single bathing in each artificial salt bath had no significant effect on the skin histamine contents. However, the skin histamine contents after a serial bathing in Na₂SO₄·NaHCO₃ (p<0.01) and CO₂ baths (p<0.05) for 3 weeks were significantly increased compared with that of tap water.
The small amount of histamine released as a chemical mediator may have caused the warming effect, as observed in type 1 allergic reaction.

The warming effect following serial bathing in the water containing Na₂SO₄·NaHCO₃ was studied in rabbits by mass spectrometry.
Rabbits, weighing about 2kg, were placed in a bath containing Na₂SO₄·NaHCO₃ (33g/20l) at 36-37°C for 20 minutes every day for 3 weeks.
By mass spectrometry, the subcutaneous tissue perfusion rate was calculated on the basis of changes in the partial pressure of Argon injected on diffusion membrane of the sensor catheter.
The mean subcutaneous pCO₂ was 46.6±14.6mmHg in the Na₂SO₄·NaHCO₃ bath group and 28.8±6.7mmHg in the control tap water group; the tissue perfusion rate in these two groups was 26.78±6.45ml/100g/min and 20.32±7.15ml/100g/min, respectively.
The warming effect of Na₂SO₄·NaHCO₃ bathing is thought to be derived from increased metabolism and micro-circulation dynamics resulting from dermal stimulation by Na₂SO₄·NaHCO₃.