With smoking getting such a bad name from scientific studies, some people - including teenagers - are turning to chewing tobacco instead. Yet, aside from the fact that it is an unsanitary and repelling habit, chewing isn't safer than smoking. It's more dangerous.

A study released this week by the chief of clinical pharmacology at San Francisco General Hospital indicates that so-called "smokeless tobacco" produces prolonged, high levels of nicotine in the blood.As a result, 30 minutes worth of chewing tobacco exposes a person to more nicotine than two or three cigarettes. Smoking two or three cigarettes in a half-hour qualifies a person as a very heavy smoker indeed.

Oral snuff was almost as bad, and even nicotine gum, used by people wanting to quit smoking, produced slightly more nicotine than a cigarette.

The researcher, Dr. Neal Benowitz, said the actual intake of nicotine absorbed from chewing tobacco may be underestimated because many users keep a tobacco wad in their mouths for hours, rather than the 30-minute limit used in the study.

Nicotine, which has been called as addictive as some illegal drugs, is one of the things in tobacco that can harm the body. It raises the heart rate and blood pressure. And chewing tobacco has been linked to oral cancer.

The lesson is clear, and it ought to be learned by teens, in particular: Whether it is smoked or chewed, tobacco is still poison.