But there are billions of other kinds that could do your body a lot of good.
Adam Jonas has colitis, "you basically feel like you need to go to the bathroom 10, 15 times a day," Jonas told Ivanhoe. "So it's pretty nasty. It's not a comfortable thing to be dealing with."
To help with his gut problem, he takes a capsule full of bacteria every day.
"It's new to hear doctors prescribing bacteria," Gregory Plotnikoff, MD, Senior Consultant at the Penny George Institute for Health and Healing, told Ivanhoe. "They're friendly bacteria, beneficial bacteria."
Called probiotics, they can be found in yogurt. The doctor says they help the body produce vitamins, pain relieving substances, and can improve digestion.
Sleep problems, surgery, stress, even antibiotics hurt the balance of good bacteria in your belly.
"40 million Americans suffer from chronic gut distress," Dr. Plotnikoff said. "Simply taking probiotics can help a large number of people."
They're helpful for most, but critically ill patients with immune system problems should steer clear of probiotics. Also, the FDA doesn't regulate probiotics for over the counter use.
If you take them, the doctor says make sure they have at least 20 billion colony forming units or CFUs per capsule. And only wash them down with filtered bottled water.
"City water has chlorine in it to get rid of bacteria," Dr. Plotnikoff explained.
Heat can also kill probiotics, so avoid coffee, tea or hot foods for at least 30 minutes before or after taking one. After taking probiotics for a while now, Adam Jonas has experienced their benefits.
"I would say I'm normal now," he said.
Probiotics are available over the counter and the doctor says a two month supply runs about $40 to $50.