What are the taboos in Colombia?

Making an O.K. sign and then placing it over your nose signifies that someone is a homosexual.
Using your two fingers to indicate length of something is an obscene gesture. Instead, extend your right arm and use your left hand to mark off distance.
Avoid making jokes about drugs, or drug consumption as they will not be taken likely. For Colombians it's not a taboo to talk about this issue, but be sure to approach it as a serious conversation, not as a stereotyped joke.

Homosexuality is not widely accepted or understood, especially by older generations. If you are homosexual, it might be best to keep a low profile.