No getting high in the underground, please!

A straphanger hellbent on stopping a vagrant from smoking pot on a crowded Manhattan subway was stabbed in the head with a pen yesterday after she yanked a lighter from his hands, sources said.

Evelyn Seeger, 45, of Nutley, NJ, was attacked by deranged stoner Cordero Coroberto, 35, on a southbound No. 2 train near 14th Street about 9:15 a.m. after he tried to light a blunt — a cigar refilled with tobacco and marijuana, a witness said.

“The argument started when he tried to light it . . . he swung at her and hit her with the pen on the forehead,” said Marc Bush, one of several good Samaritans who pinned Coroberto in a corner until the train arrived at Chambers Street, where cops were waiting on the platform.

Seeger was rushed to Beekman Hospital, where she was given a tetanus shot, treated and released.

Coroberto was charged with second-degree assault, criminal possession of a weapon and possession of marijuana.

His priors include dozens of busts for sleeping on the subway, turnstile jumping and criminal mischief.