The user steals 1/16 of the target's max HP (or more if used in conjunction with Toxic) until either Pokemon uses Haze or the target is switched out or KO'ed; does not work on Grass-type Pokemon, but will work against Pokemon behind Substitutes.
Verdict: Suprisingly, despite being a starter Pokemon, Venusaur is one of the lesser Grass Pokemon in RBY, because it can't do that much despite its well-rounded stats. Razor Leaf is pretty much its only choice for STAB (as Venusaur's has a 99.6% chance to CH), and, since it doesn't learn Stun Spore for some reason, you have to rely on Body Slam to inflict paralysis and damage things that resist Grass. Sleep Powder and Leech Seed are solid utility moves as always, but it is a shame that Venusaur would have to choose between them to fit a stat-boosting move into its arsenal. He is unfortunately pretty limited.