1) Water

When you drink more water than your kidneys can handle, you can upset the balance of sodium levels in your blood — this is called water intoxication. Water intoxication mostly occurs when water is being consumed in a high quantity without adequate electrolyte intake.

Water may seem like the least harmful substance, but drinking too much of it can kill.

2) Taking Too much Caffeine

Too much caffeine can kill. There have been numerous deaths attributed to excessive caffeine ingestion. So if you happen to be a person who loves coffee and energy drinks, you might want to know approximately what amount you should avoid drinking on a given day. 

3)Tomatoes

Tomatoes

The juicy, red fruit contains a poison, Glycoalkaloid, in its leaves, which is known for causing upset stomachs, severe cramping, and anxiety. So steer clear of the leaves and stems.

4) Shell Fish

eating shellfish that is contaminated with algae that contains Paralytic Shellfish Toxin ( PST ), a toxin harmful to humans. This toxin is extremely poisonous; as little as one milligram (0.000035 ounce) is enough to kill an adult.

5) Potatoes

Ordinary potatoes, if consumed at the wrong time, can be dangerous. The leaves, stem, and sprouts of a potato contain glycoalkaloids, a poison found in flowering plants called nightshades, of which a potato is one.