俱舍論記 14.184

14.184

「又令醉亂至茅端所霑量」者，通第二極少不飲證。醉亂不定，故遮極少。如性不便，飲少亦醉，經遮不飲意在於茲，非言性罪經遮不飲。如有性便多亦不醉，為病飲少，理亦應通。

[On the phrase,] "Furthermore, causing drunken confusion [...] the amount touching the tip of a blade of grass": This resolves the second proof: not drinking even the smallest amount. Drunken confusion is variable, so even the smallest amount is prohibited. Just as one who is constitutionally unfit becomes drunk even on a small drink, the sūtra's prohibition against drinking has its intention here; it is not that the sūtra prohibited drinking because it is a natural offense. If one is constitutionally fit and does not become drunk even with much, drinking a small amount for illness logically should also be permissible.