There are several herbs and vegetables that can be toxic or poisonous if consumed improperly or in large quantities. Some are commonly known, while others might be surprising. Here's a list of some notable ones:

  1. Rhubarb Leaves: While rhubarb stalks are safe and commonly used in cooking, the leaves contain oxalic acid and anthraquinone glycosides, which can be poisonous.

  2. Nightshade Family (Solanaceae):

    • Potatoes: The green parts of a potato (including green skin and sprouts) contain solanine, a natural toxin. Consuming large amounts of green potatoes can lead to solanine poisoning.
    • Tomatoes: Similar to potatoes, the green parts of a tomato plant contain solanine.
    • Eggplant: Also contains solanine, though in smaller quantities than green potatoes or tomatoes.
    • Belladonna (Deadly Nightshade): Highly toxic; even a small amount of the plant or berries can be fatal.
  3. Foxglove (Digitalis): While not typically thought of as a vegetable or herb for consumption, it's important to mention due to its high toxicity. It's used medicinally for heart conditions but is dangerous if consumed incorrectly.

  4. Castor Beans: The seeds contain ricin, one of the most toxic naturally occurring substances. Even a single bean can be lethal if ingested without proper preparation.

  5. Ackee Fruit: The unripe fruit contains hypoglycin A, which can cause Jamaican Vomiting Sickness. The fruit is safe to eat when properly ripe and prepared.

  6. Bitter Almonds: While not a vegetable, they are worth mentioning. Bitter almonds contain amygdalin, which can convert to cyanide when ingested. They must be processed to remove the toxins before consumption.

  7. Parsnips: Wild parsnips contain furanocoumarins, which can cause skin problems and should not be consumed in large quantities.

  8. Cassava (Yuca): Both sweet and bitter cassava contain cyanogenic glycosides, which can release cyanide when the plant is damaged or eaten raw. Proper preparation is essential to avoid poisoning.

  9. Mushrooms: While not a herb or vegetable, it's important to mention them as some wild mushrooms are highly toxic (e.g., Amanita phalloides, also known as the death cap).

  10. Elderberry: The raw berries, leaves, and other parts contain a cyanide-inducing chemical. They need to be properly cooked before consumption.

  11. Datura (Jimson Weed): All parts of Datura plants are toxic and can cause delirium, hallucinations, and potentially death if ingested.

It's important to note that many of these plants are only toxic if consumed inappropriately or in large amounts. In many cases, proper preparation can mitigate the risks. Always be cautious with wild plants and mushrooms, and never consume them unless you are absolutely certain of their safety and have expertise in identifying them.