Diarrhea

Diarrhea is caused by either a weak digestive fire or increased pitta. When food is not properly digested or absorbed, it passes out in semi-liquid or watery form. Improper eating habits, such as eating food which the system cannot digest, eating a meal before the previous one is digested, and irregular eating habits, are some of the common causes of diarrhea.
Diet
Most people have a general idea of the foods which cause these problems. For example, if a person feels heaviness, uneasiness, wind, distention or stomach ache immediately after eating a certain food, it indicates that the particular food is not easily digested. Generally, foods which are fried in oil or ghee (clarified butter), meats, vegetables like cauliflower, broccoli, beans, nuts and sweets are difficult to digest. So they should be eaten less frequently and in small quantities.
Eating contradictory (incompatible) foods, such as taking milk and citrus fruits simultaneously, can cause digestive upsets. Impure food or water, eating food which the system is not used to, infection of the alimentary canal, or psychological factors like grief and nervousness can also lead to diarrhea.
Some Home Remedies
Add one teaspoon of fresh grated ginger and one gram of nutmeg powder to half a cup of water. Blend them together for few minutes into a mixture. Drinking this twice or thrice a day helps to stop diarrhea.

In cases of excessive thirst, water boiled with coriander seeds should be given (after straining). Pomegranate juice in small quantities can be also given frequently.
A decoction prepared from pomegranate skin is very useful in stopping diarrhea. To prepare the decoction, take 50 grams of fresh pomegranate skin. Soak it in 800 ml. of water for one hour. Boil until a quarter of the volume remains (200 ml). Store this mixture in a clean, dry bottle. A couple of tablespoons can be taken several times a day. If there is blood in the stools, add half a teaspoon of honey to the decoction.
Another helpful remedy is a sugar and salt solution. Mix one teaspoon of sugar and half a teaspoon of common salt in a cup of water. Small doses of this mixture (around a quarter cup) can be given whenever the patient wants to drink.
A paste made of sesame seeds (1 teaspoon) and a few tablespoons of goats milk is also beneficial. 
Regimen
Fasting helps in digesting toxins in the intestine, although it should not be practiced if the patient is weak. As the absorption power of the intestines is very low, the patient should not eat too much at one time. The principle is to eat less, but more frequently if necessary.
The diet must be easy to digest. Only foods that bind the stool like yogurt, rice, banana, apple and pomegranate should be taken in the beginning. Easily digestible foods like boiled vegetables, boiled rice, khichadi and fruits should be eaten. Khichadi is prepared by cooking together rice and mung dal (green lentils). Digestive spices like cumin, coriander, ginger, turmeric and cardamom should be used for cooking.
Liquids should be given in small quantities (3 or 4 sips) at one time, though it can be given more frequently—at intervals of thirty minutes. Fruit juices can also be taken in small quantities.
Patients should take complete rest until they gain enough strength and energy. Physical exertion of any kind like exercise, sexual activity, sports, singing, dancing etc. should be strictly avoided. The mind should be relaxed and free from all kinds of tension. A gentle oil massage on the head is also helpful.