Clinical trial, with positive findings, conducted at a university health clinic in South Africa on 30 adult subjects with an allergy to cats. Half of the subjects were randomly allocated to receive a homeopathic combination of cat saliva and histamine; the other half received a dummy medicine (placebo). They did not know which treatment group they were in. After 4 weeks, the subjects who received the homeopathic medicine had a lesser degree of inflammation (wheal) after a skin-prick test than those who received placebo.