Food Poisoning
Although already mentioned as being caused by bacteria, it cannot be repeated enough that contaminated liquids and food are a gateway for bacteria and other parasites to enter the body, agitate your system, and cause diarrhea. Food poisoning may also cause an upset stomach, cramping and vomiting, depending on the severity. Symptoms appear within six to eight hours of ingestion.
The culprits are usually Campylobacter, E. coli, Shigella, Listeria, and Salmonella. These bacteria strains are commonly found in raw vegetables, eggs, raw and undercooked fish and meat, shellfish, unpasteurized dairy milk, and food that has not been properly stored or left to sit out at room temperature.
To prevent food poisoning, you should always thoroughly inspect and wash your food before cooking and eating. Also, washing you hands before handling food is key. Be sure to wipe down all surfaces where raw food as been placed, as well.
