Dera user Thank you for asking on HCM. Hypothyroidism is a condition in which the thyroid does not produce a sufficient amount of hormones necessary for the cells throughout the body to work properly. Diarrhea is not unheard of with hypothyroidism and is thought to be a result of small intestine bacteria overgrowth (SIBO). In our practice we see sinjificanc beetwen patiens with Hashimoto’s disease (autoimmune codition )and diarrhea. In these case you are at increased risk for celiac disease. Diarrhea is most common in hyperthyroid .(must t o check Thyroid hormone level) In my opimiom : Diarrhea in hypothyroidism: bacterial overgrowth as a possible etiology. You must to check blood test : TSH , Ft3, Ft4 , TSI Hypothyroidism more often can result in constipation and bloating. May I know please your Last blood test for thyroid hormone ? Did you taking your medication(Synthroid) as prescribed by doctor? How often is the diarrhea? I must t o say that : Diarrhea is a less frequent symptom with hypothyroidism and as discussed above, may be related to the development of SIBO secondary to the slowed motility resulting from the thyroid dysfunction. SIBO diagnosed through the use of a hydrogen breath test and is treated with specific antibiotics. For more information, you must t o consout with gastroenterology for futher information .Endocrinolog doctor after you have done thyroid leve hormone . Hope i Answer your questation .Please contact me for futher informacion Bets Regards Dr Klodiana Poshi