What are the psychedelic effects of (star) anise and how many people are affected?
Interesting question! As this post has been sitting around for a while I am going for some speculations. First you talk chocolate, which essentially contains the alkaloid theobromine. Anise contains the propenylbenzene (E)-anethole (Idle, 2005). Theobromine is a caffeine-derivative and basically produces alertness, but also restlessness and perhaps anxiety when administered in large amounts (wiki). In extremely high doses there can be LSD-like effects (anecdotal report). Perhaps (speculative) your girlfriend is especially sensitive. Then (E)-anethole: the late Alexander Shulgin, Godfather of MDMA, has made the etheric oils (in)famous as precursors for amphetamine synthesis. In themselves the propenylbenzenes like (E)-anethole are quite harmless, as they do not contain an amine group (a prerequisite for being called an alkaloid). However, heating (E)-anethole in the presence of ammonia may lead to the production of PMA, a compound structurally and neuropsychopharmacologically related to MDMA (Idle, 2005). Although a bit of chocolate and a sip of Sambuca do not meet any of these conditions, both chocolate and Sambuca do contain certain psychoactive compounds, or their immediate precursors.