Unfortunately, it is true that Thai food tends to cause diarrhea for many people. This is especially true if it is one of the first times in your life you are eating Thai food.
There are a couple different reasons why Thai food can cause diarrhea. First, Thai food is very spicy and intense and it can be difficult for your digestive system to deal with at first.
After a short period of adjustment, however, you will be less likely to get diarrhea or an upset stomach from Thai food. Your gut simply gets accustomed to dealing with it.
Secondly, there can be different types of bacteria in Thai food than what your body is used to. This won’t be is applicable if you are ordering Thai food in your home country.
But if you’re traveling to Thailand, be prepared to deal with travelers diarrhea caused by bacteria not native to your home. This is true not only of Thai food, but of any location that you may travel in the world.
I live in Thailand and have had to deal with my fair share of diarrhea over the years. I have found that avoiding street vendors that sell Thai food is a good idea. These vendors do not always have the cleanest sanitary conditions, and they tend to cause diarrhea more frequently.
I recommend using Pepto-Bismol to deal with diarrhea. It is cheap, easy to find, and tends to stop diarrhea in its tracks. In Thailand, all the local pharmacies sell a generic Pepto-Bismol called Gastro-Bismol. It comes in tablets that you can carry easily in your pocket, too.
Bonus tip: be very wary of feeding Thai food to dogs as it can cause them diarrhea, too. Rinse off the meat with water to get the spices off before feeding Thai food to dogs.