There seems to be a need for a bit more information about what plants are nightshades and why they are a problem. Part of this confusion in macrobiotics comes from the conflict between smoking cigarettes and eating nightshade foods, with most of the leaders being smokers and therefore unable to reconcile addiction to nicotine with avoidance of solanine, which is the same chemical compound. Ohsawa wrote a pamphlet that was withdrawn in the late 1960s in which he argued that the yin smoke in a cigarette went up into the air but this conflicts with all the evidence that the nicotine, which is the addictive drug in tobacco and other nightshades, goes straight into the lungs. It's a pity they never straightened this out as it undermined the macrobiotic argument for a lot of otherwise favorably inclined people.

For the full story on nightshades modesty does not forbid me to say that the best exposition of what they are and what they do was written by me and can be found at http://www.craigsams.com/pages/tobac.html

Enjoy!

Craig