Causes of loose and watery stools, or diarrhea, include the stomach flu, food allergies, laxative abuse, Crohn’s disease and hyperthyroidism, according to WebMD. Other causes include medications, diabetes and alcohol abuse.
The stomach flu is caused by food poisoning or passed through close contact with an infected person, as noted by MedlinePlus. The most common viruses responsible for the stomach flu include the norovirus, rotavirus, astrovirus and enteric adenovirus. In addition to loose, watery stools, patients with the stomach flu experience symptoms such as nausea, abdominal pain, vomiting and fever.
Crohn's disease is a chronic condition that occurs when the bowel becomes ulcerated and inflamed, according to Cleveland Clinic. The disease affects the function of the bowel, causing it to swell, develop fistulas and lose its ability to properly absorb nutrients from food. Symptoms of Crohn's disease occur during flare-ups and include rectal bleeding, fever and weight loss.
Hyperthyroidism is a condition that occurs when there is too much thyroid hormone produced in the body, as reported by MedlinePlus. Causes of hyperthyroidism include Graves disease, thyroiditis and consuming too many iodine rich foods. Patients with hyperthyroidism experience symptoms such as frequent bowel movements, heat intolerance, weight loss, sleep problems and increased sweating.