The immersion bath tub should be filled with about 135 litres of hot water at 400C. One to 1 1/2 kg. of Epsom salt should be dissolved in this water. The patient should drink a glass of cold water, cover the head with a cold towel and then lie down in the tub, completely immersing the trunk, thighs and legs for 15 to 20 minutes.
The best time to take this bath is just before retiring to bed. This is useful in cases of sciatica, lumbago, rheumatism, diabetes, neuritis, cold and catarrh, kidney disorders, and other uric acid and skin affections.
Certain precautions are necessary while taking these therapeutic baths. Full baths should be avoided within three hours after a meal and one hour before it. Local baths like the hip bath and foot bath may, however, be taken two hours after a meal. Clean and pure water must be used for baths and water once used should not be used again. While taking baths, temperature and duration should be strictly observed to obtain the desired effects. A thermometer should always be used to measure the temperature of the body.
Women should not take any of the baths during menstruation. They can take only hip baths during pregnancy till the completion of the third month.