Influence of Drugs
Question
How long after one is under the influence of marijuana can he participate in signing a halacha contract
Answer
Shalom!
Thank you for your question.
That being said, a person must not get involved in a halachic matter while under the influence of alcohol or drugs. This includes even a slight blurring of the senses.
With regard to alcohol, this is generally understood as consuming about 5 oz of wine though it varies from person to person.
The same is true with regard to marijuana. Once one has consumed a quantity that begins to blur one’s senses one is not to be involved with a halachic matter.
The ban continues until one is certain that the influence has left one’s body and one is again focused.
SOURCES: Y.D. 242 with commentaries