What is a common symptom of foodborne illness?

Diarrhea is a common symptom of foodborne illness because it is a response to the presence of harmful pathogens or toxins in the gastrointestinal tract. When contaminated food or beverages are consumed, the body often reacts by expelling these harmful substances, leading to diarrhea. This symptom can occur alongside other gastrointestinal issues such as vomiting, abdominal cramping, and nausea, all of which are typical responses to foodborne pathogens as the body attempts to rid itself of the infection.

While headaches, loss of appetite, and muscle aches can occur in some illnesses, they are not as directly associated with foodborne pathogens as diarrhea. Diarrhea is a primary indicator often used by medical professionals to identify foodborne illnesses, making it the most relevant and recognized symptom in this context.