Hello, You are having redness on the inner thighs while having diarrhea. You took anti diarrheal medicines. The commonest cause of such symptom is lack of heat or airflow. Rashes are more on the areas where sweating is more. Due to this, the chances of getting bacterial or fungal infection increases even more. The rubbing together of thighs also gives rise to more rash, skin irritation or itchiness. Fungal infection (jock itch) can be a reason, heat rash, contact dermatitis, syphilis, genital herpes can be the other factors for the symptoms. You are suggested to take care of your hygiene, bath regularly. Do not share your toiletries, avoid use of harsh and perfumed lotions and soaps. Wear loose fitting cotton clothes. Wash your clothes and bed sheets in hot water frequently. You can apply Neosporin ointment or Silverex ointment on the affected area for relief. Sometimes, side effect of medicines you are taking can also manifest such symptoms. You can take boiled, mashed raw bananas with bread or toast, it will naturally help to stop diarrhea. Taking well boiled sago pearls in water with a little sugar also helps to control diarrhea naturally. In case the rashes do not go away, get clinically examined by a dermatologist, get STD tests done to stay on the safer side. You will be treated accordingly. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician