Diarrhea and headache may be due to gastrointestinal colds, bacterial enteritis, improper diet, and systemic infections. It is recommended to visit the hospital promptly to determine the cause and treat the cause. Common causes and treatments are as follows: 1. Gastrointestinal flu: headache and diarrhea are more common in gastrointestinal flu caused by viral infection, and in most cases, the condition is self-limiting. In this case, you can use aspirin, acetaminophen and other antipyretic and analgesic agents to relieve headache symptoms, and when diarrhea is serious, use antidiarrheal and protective drugs such as montelukast, enteritis, etc.; 2, bacterial enteritis: headache and diarrhea may also be caused by bacterial infection causing intestinal inflammation. The cause of the disease is clear and treatment is given. If the body temperature is too high, antipyretic drugs such as paracetamol can be used to reduce fever and relieve headache. If the diarrhea is severe, if bacterial infection is identified, norfloxacin or safranin hydrochloride can be used, together with montelukast treatment, to relieve the symptoms of diarrhea; 3, improper diet: consumption of unclean, spicy, fried, stimulating food may also lead to symptoms of abdominal distension and headache. Patients usually need to pay attention to dietary hygiene, adjust the diet structure, diet as light as possible, do not eat spicy, irritating and too greasy food; 4, systemic infection: systemic infection is the invasion of germs into the human blood circulation, and in the body to grow and reproduce, produce toxins and cause serious systemic infection or poisoning symptoms, patients will also appear headache, diarrhea. When systemic infections occur, you should seek medical attention and treatment options under the guidance of a doctor.