The drinks industry funded group has complained to TV watchdog OFCOM and the BBC about a recent show which ended with a scene featuring two medics in a bar.
Actors were shown downing five shots of tequila each, and there was an implication that they were going to have sex, the group said in a statement.
The Portman Group also said there was no portrayal of the harmful effect of the characters' drinking.
Portman Group chief executive David Poley said: "We appreciate that programme makers want to mirror some aspects of real life but they should avoid the encouragement of harmful, rapid and excessive drinking. We would not advocate censorship, nor deny that storylines of alcohol misuse can be used to good and positive effect.
"But in this case, the characters drunk far too much and the harmful consequences were not shown. There are strict controls on alcohol advertising and marketing, but the impact of these rules is being diluted by irresponsible programming."