In order to study epidemiological characteristics of patients with “Oketsu” (blood stagnation), we compared patients suffering from “Oketsu” with those who visited our departments of internal medicine for the first time (including those with “Oketsu”). In order to eliminate ambiguity, we defined patients with “Oketsu” as those who responded to drugs designed to overcome “Oketsu”. “Oketsu” was more common among slightly fat, middle-aged females and less common among young slender patients. “Oketsu” was noted more in patients who had a history of surgery (especially gynecological surgery), induced abortion, and abnormal delivery and in patients with chronic disease and gynecological disorders. In young patients, “Oketsu” was associated with obesity and gynecological disorders. In middle-aged patients, it was associated with a history of disease, and in older patients, it was associated with current disease. In slender patients, “Oketsu” was associated with a history of induced abortion, and in those with normal weight it was associated with a history of disease. Other factors were comparable to those of controls. Middle age, a tendency to obesity, and a history of disease are all independently related to “Oketsu, ” and “Oketsu” often seems to be related to only one of these factors. Those with “Oketsu” could be categorized into two groups, namely group (1) with a history of a high incidence of disease (those of middle age and with normal weight) and group (2) with comparable incidence of a history of disease. Group (2) comprises those with a tendency of obesity (young and old patients) and non-obese patients (middle-aged ones).