Youcat commented through CCC – Question n. 389.

YOUCAT Question n. 389 - Why is it a sin to take drugs?

(Youcat answer) Using drugs is a sin because it is an act of self-destruction and thus an offense against the life that God has given us out of love.

A deepening through CCC

(CCC 2290) The virtue of temperance disposes us to avoid every kind of excess: the abuse of food, alcohol, tobacco, or medicine. Those incur grave guilt who, by drunkenness or a love of speed, endanger their own and others' safety on the road, at sea, or in the air. 

Reflecting and meditating 

(Youcat comment) Every form of a person’s dependence on legal substances (alcohol, medication, tobacco) and even more so on illegal drugs is an exchange of freedom for slavery; it damages the health and life of the person concerned and also does great harm to the people around him. Every time a person loses or forgets himself by becoming intoxicated, which can also include excessive eating and drinking, indulgence in sexual activity, or speeding with an automobile, he loses some of his human dignity and freedom and therefore sins against God. This should be distinguished from the reasonable, conscious, and moderate use of enjoyable things.  

(CCC Comment)

(CCC 2291) The use of drugs inflicts very grave damage on human health and life. Their use, except on strictly therapeutic grounds, is a grave offense. Clandestine production of and trafficking in drugs are scandalous practices. They constitute direct co-operation in evil, since they encourage people to practices gravely contrary to the moral law.  

(The next question is: Is it permissible to experiment on a live human being?)