Dictionary.net

from diluo, (dis, and luere,) 'I wash away.' (F.) Delayants. Medicines which have been conceived proper for augmenting the fluidity of the blood and other animal liquids. All aqueous drinks are diluents. They are administered, with great advantage, in various diseases. In fever, water, which is the most familiar diluent, may be freely allowed; the only precaution being to give it hot in the cold stage, cold in the hot, and tepid in the sweating. In diseases, where it is considered necessary to abstract blood largely, diluents should not be given too freely. The abstraction of blood occasions activity of absorption, and the mass is speedily restored. It is also obvious, that in cases of inflammation of the mammae, in nurses, diluents should not be freely allowed, as they increase the secretion of milk, and add to the irritation. When demulcents are exhibited in cases of urinary disease, they act simply as diluents; their mucilaginous portion is digested in the stomach and small intestine, the watery portion alone being separated by the kidney.