Helium-neon laser has first been shown to be an active interferon indu
cer. Marked induction was found at various radiation power (1, 6-7, 20
MW) and at various radiation exposures: from 1 sec to 1 min both for
single (up to 512 units/ml) and repeated (up to 1024 units/ml) effects
on leukocytes of the donor blood. The major part of interferon was sh
own to be acid-labile and a lesser part was acid-stable alpha- and gam
ma-interferons. The above data are of both practical and theoretical i
mportance for the elucidation of the pathogenetic mechanisms of positi
ve therapeutic effect of this light on living beings.