NOTS is an acronym for Naturally Occurring Toxic Substances. There are many of them which are found in common food items. I would like to introduce you to some of them so that when you pick those Apples or Mushrooms next time at the departmental store or local vegetable market, you would think again for the potential health hazards and how to avoid them.

Fungal Toxins

Death Cup Mushroom (Attribution: Picture By Archenzo (Own work) [GFDL ( or CC-BY-SA-3.0 (], via Wikimedia Commons Under GFDL

Death cup mushroom are highly toxic. A single mushroom can be lethal for an adult. The symptoms of poisoning are predominantly gastrointestinal(GI) in nature. The toxin eventually kills due to hepatoxicity. An image of the Death Cup Mushroom is shown on the right. Now, what is hepatotoxicity? “Hepatotoxicity means liver damage by chemicals! There has been a lot of such cases due to overdose of certain drugs.”

Hydrogen Cyanide (HCN)

It is a well-known toxic chemical (We have all heard the term Cyanide Poisoning! Right?). HCN is found in raw or unprocessed cassava and bamboo shoots. Bamboo shoots or the bamboo sprouts are used as traditional pickles by many tribes in the North Eastern states in India. The soots of bamboo are also used as additive in many traditional cuisines, (e.g., Chicken with bamboo shoots). It can be found in quantities as large as 1g/Kg. It is also found in fruits which have a pit like apples, cherries, apricots and bitter almonds. They contain small amounts of cyanohydrins such as mandelonitrile and amygdalin which slowly releases HCN.

Chemical structures of mandelonitrile and amygdalin. Drawn using Chemical Structure drawing software ChemDraw.
Image Source:

“We should eat our Apples without the seeds!”


These are stress toxins and released in response to stress such as physical damage. They can cause GI problems and allergic reactions in susceptible people. These toxins are present in parsnips which are closely related to carrots and parsleys. Below are two isomers of furocoumarins.

Parsnips should always be peeled and cooked before consumption!”


These are common in stress toxins concentrated in bitter tasting sprout and peel common in Potatoes. The chemical that is present in the green part of potatoes is called Solanine. It is a glycoalkaloid poison found in species of the nightshade family within the genus Solanum, such as the potato (Solanum tuberosum), the tomato (Solanum lycopersicum), and the eggplant (Solanum melongena).

Chemical structure of α-Solanine; Image Attribution: By Original: Calvero Vector: Calvero (Own work) [Public domain], via Wikimedia Commons

Solanine was first isolated in 1820 from the berries of the European black nightshade (Solanum nigrum). According to one study, toxicity appears at a level of 2-5 mg/kg body weight, with LD-50 (lethal dose) values at 3-6 mg/kg body weight.

How to avoid potential poisoning?

Simply, cut off sprouts and peel off green potatoes.

Fact is, cooking cannot destroy Gylcoalkaloids!


These plant toxins are found in kidney beans such as red kidney beans. Soaking in water for few hours and followed by boiling will leach it.

Oxalic acid

Rhubarb (a plant, the stems of which are used in making pies and other desserts) contains oxalic acid. The leaves contain high amounts. This acid can cause neurological , cardiac, respiratory, and GI effects.

Image Attribution: By RhubarbFarmer (Own work) [CC BY-SA 3.0 (], via Wikimedia Commons



They can be found in zucchini. Bitter tasting zucchini must not be consumed. It can cause severe gastrointestinal problems.

There are many other toxins that occur in many fruits and vegetables naturally. Consumption of toxic NOTS can be very dangerous in some cases.

Proper information about different foods that we consume and their potential toxic effects can help us avoid future risks of toxicity.