Mapacho, the tobacco ingested by shamans in the Amazon, is a species containing very high levels of nicotine and other psychoactive pyridine alkaloids — indeed, the highest nicotine levels of any tobacco species; leaves from this species contain more than eight percent nicotine, as much as twenty-six times the amount found in the common cigarette tobacco in North America. There is also reason to believe that psychoactive alkaloids other than nicotine are present in noncommercial varieties of tobacco.
There is little doubt tobacco by itself has psychoactive effects, including the ability to induce hallucinations. The nicotine alkaloid in tobacco displays high acute toxicity, and acute nicotine intoxication can have significant visual and auditory effects, including what anthropologist Johannes Wilbert, an expert on tobacco use in South American shamanism, calls “hallucinatory eschatological scenarios on a cosmic scale.”
It is difficult for North Americans to think of tobacco as a hallucinogen, in large part because the tobacco species used in commercial North American cigarettes have such a relatively low nicotine content, and because North American smokers ingest relatively small quantities, generally stopping when the desired mood alteration has been achieved. Interestingly, there have been scattered reports of hallucinations associated with smoking while wearing a transdermal nicotine patch.
Nicotine is acutely toxic, so I would strongly discourage unsupervised experiments.