Ma'anar ƙamus na kalmar "antihistamine" magani ne ko magani wanda ake amfani dashi don magance tasirin histamine a cikin jiki. Histamine wani sinadari ne na halitta da jiki ke fitar da shi don mayar da martani ga wani abu mai ban sha'awa ko wani abu mai ban haushi, kuma yana iya haifar da alamu iri-iri kamar iƙirari, atishawa, hancin hanci, da idanu masu ruwa. Antihistamines suna aiki ta hanyar toshe masu karɓar histamine a cikin jiki, wanda ke taimakawa wajen rage ko kawar da waɗannan alamun. Ana amfani da su da yawa don magance alerji, zazzabin hay, da sauran yanayin da ke haifar da amsawar rigakafi da yawa.