Children may contract infection from sandboxes contaminated with petsâ stool. Certain types of immature worms may penetrate through your skin during swimming or walking barefoot; when they reach the small or large intestine they grow into adult worms. Common garden worms usually do not cause illness in human.
People with lactose intolerance do not produce enough of the lactase enzyme to break down lactose. Instead, undigested lactose sits in the gut and gets broken down by bacteria, causing gas, bloating, stomach cramps, and diarrhea. Lactose intolerance is fairly common and seems to affect guys and girls equally.
Bacteria in the colon break down some of the lactose, producing hydrogen gas. The remaining lactose also draws water into the colon. The extra gas and water result in symptoms, such as cramping, diarrhea, bloating and flatulence (gas). Lactose intolerance usually is genetic (inherited). In many people of African or Asian descent, the body begins making less lactase around age 5.