A man who allegedly threatened to murder Dr. Drew Pinsky's family was arrested Wednesday and charged with felony stalking ... TMZ has learned.

Dr. Drew tells us Charles Pearson has been sending him threatening messages over the Internet ... including one in which Pearson said he would kill Dr. Drew's children and make his wife eat them.

Dr. Drew also says Pearson believes Dr. Drew has placed a tracking device in his genitals.

We're told Pearson was arrested Wednesday at Pierce College in Woodland Hills, CA. He's being held on $150,000 bail.

Dr. Drew tells TMZ this is a very serious matter and that he hopes Pearson "gets the treatment he clearly needs."