The anus is usually not swollen and painful because of the hot weather, but the hot weather and the humidity of the anus area is easy to breed bacteria, leading to anal infection, causing perianal abscess, sinusitis, resulting in anal swelling and pain; in addition, anal swelling and pain may be caused by hemorrhoids. Hot weather is not the direct cause of anal swelling and pain, mainly due to the hot weather, the perianal humidity is easy to complicate bacterial infection, causing perianal abscess and sinusitis, inflammation stimulation of the perianal area leading to redness, swelling and pain, sometimes accompanied by elevated body temperature, can be taken under the guidance of a physician cefixime, levofloxacin and other drugs for treatment. In addition, hemorrhoids inlaid or complication of infection, will lead to hemorrhoid nuclei swollen out of the anus, and cause anal swelling and pain; inlaid lighter hemorrhoids can be returned to the hemorrhoids, inflammatory hemorrhoids can be in the physician’s guidance of oral cefaclor, amoxicillin and other anti-inflammatory drugs treatment. When the weather is hot, anal swelling and pain, should go to the hospital in a timely manner, improve the examination, give targeted treatment after a clear cause, to avoid aggravation of the condition.