No Stupid Questions

• Heavy metals: lead, mercury
• Arsenic in small doses over a long period

I don’t know of any plants, but I do know that the leaves of nightshades (potato, tomato, eggplant, capsicum, tobacco) are ~~poisonous~~ toxic in large doses.

Whole maybe not “poisons” by definition I have a couple scary stories of people working in damp, moldy office and basement environments and after a couple years getting rare autoimmune and neurological disorders that killed them. One being my uncle, my family tried to get his workplace to test where he worked because the doctors said that’s most likely where he contracted it, but they refused. We weren’t looking for money, just trying to save the next guy. I was fairly young when this happened so I don’t remember all the details.

Apple seeds contain cyanide, simply crushing them will release the poison and it can be added to something else, although it's not very slow.

There's also the Destroying Angel/Death Cap mushroom, whose symptoms can take up to a day to even start, by which point the toxins have been incorporated and destruction of liver and kidney tissue is irreversible. They also contain toxins that can cause severe DNA damage, making it so your body can no longer repair itself after exposure, and you slowly die cell by cell.

I'm thinking metal poisoning over time. Lead or copper, for example.

Alcohol. Sometimes it takes 30 or 40 years to be effective. Not very good for murder, but wildly popular for suicide.

Mushroom poisons usually are slow actors. They take a few days while they kill your liver, and then you'll follow suit.

I’m neither a writer nor a scientist, but there’s a copy of this on my bookshelf and I wish I could lend it to you: Deadly Doses: The Writer’s Guide to Poisons

Does anyone remember when the writer googled a recipe for their historical novel and copy pasted the first result - which turned out to be fictional from Zelda BOTW

edit: https://www.theverge.com/tldr/2020/8/3/21352299/zelda-breath-of-the-wild-red-clothes-dye-traveler-gates-of-wisdom-john-boyne-google-search-results

I recommend an American diet: ultra-processed foods, excess sodium, saturated fat, refined grains, calories from solid fats and added sugars, and avoid vegetables like the plague! The target will be dead within 50 years...

well you can try to look it up - slow acting poisons in minecraft.

on a more serious note, as others have noted heavy metal poisoning like mercury or lead.

I have another one - sulphur. Readiy available throughout ancient times, and non-toxic by itself (S8 form that is). But many of it's compounds are toxic in varying degree. You can look its wiki page (https://en.wikipedia.org/wiki/Sulfur) for some commonly available toxic salts, but I also have some ideas to incorporate in story - burning of sulfur (in incomplete form producing SO2 https://en.wikipedia.org/wiki/Sulfur_dioxide). You can incorporate it very easily (someone tampered someone elses fireplace or incense sticks if we also want to hide any wierdities with flame). By itself it iis not very toxic, almost odorless, and not a strong color. It has existed even in food stored for long time due to degradation of sulfur containg organic compounds, wiki page also lists that wine this (another potential vector to supply this). When in body, it can produce H2SO3 (sulphurous acid) and by inhaling/ingesting small amounts for long time - it will gradually destroy alveoli/stomach inner lining and liver. Sulfur by itself is very cheap (you can find ores in a lot of places around the world, relatively easy to mine, also found near volcanic places), humans have used it in trying to make medicine out of it, and it has huge amount of history in alchemy (https://en.wikipedia.org/wiki/Alchemical_symbol, https://www.thoughtco.com/tria-prima-three-primes-of-alchemy-603699). In fact, since it is present in humans naturally, and msot organic matter for that matter - small amount of sulfur being present in someones' reports will not raise a special eye, and they would just be recommended to not eat food that is traditionally know to have much sulfur (for example garlics (https://en.wikipedia.org/wiki/Allyl_isothiocyanate). Garlic extract can also be used to deliver large amount of isothiocynate, but this would be a seperate method of poisoning all together - it is much more lethal, so not very slow acting, but one can keep giving a dose of this below lethal dose to keep damaging liver, and a final blow sometime.

I hope you find this helpful, and I hope no villagers in minecraft are killed by this.

At work I learned that cyanide is actually very dangerous because it accumulates its effects. Like you have a little now and a little later, then suddenly you can't get up from bed so you call in sick. Its dangerous stuff.

Yeah, in a historic setting, use something readers will recognize, as well. Arsenic, Mercury, that kind of thing. They've been used as a poison, and have accidentally poisoned, for so long that they're tropes of their own. Both of those in specific were available in the region you're using.

Plus, they're going to be really easy to describe the actions of, and don't require medical knowledge to understand the effects of. Well, the stuff that's going to be useful to show on page anyway, the stuff that happens inside organs might take a little.

In almost every case in fictional writing it's better to make up a poison then use a real one. That way you don't have someone picking it apart later. Also you can give it whatever properties you want/need. Now excuse me while I continue to work on my immunity to iocane powder.

What do you mean by slow? Time till symptoms? time till death? Hours? Days? Weeks?

Raw castor beans contain ricin its a cool looking plant that gets big. My neighbor grew on once accidentally.

symptoms commonly begin within two to four hours, but may be delayed by up to 36 hours.

Unless treated, death can be expected to occur within 3–5 days; however, in most cases a full recovery can be made.

Actually a lot of beans are toxic when raw, but not deadly. Raw lima beans are special though; they contain something that the human body breaks down into cyanide. No clue how long that takes or how many it would take to cause harm.

Heavy metals (mercury, arsenic, cadmium, lead) are known for building up over time with many exposures. Think mad hatter syndrome, etc. but exposures can also be acute if high enough. IIRC acute arsenic poisoning makes you vomit and diarrhea until you die of dehydration after days or weeks.

Time. It's very slow but will get them in the end.

Heavy metals in artists’ oil paints.

You can always dig into true crime, see what methods are used to kill husbands.

Check out ChubbyEmu on YouTube. He’s a pharmacist who presents strange and interesting medical stories (with dramatic re-enactments) involving unusual chemical exposures that damage and sometimes kill people. Examples: soda, coconut water from a bad coconut, a fermented soup, ivermectin ordered online, lab chemicals stolen by a student and given to a disliked roommate, and so on. Maybe something there will inspire you. ChubbyEmu does a good job of breaking down complex medical into an easily digestible format.

Apple seeds contain cyanide, and are easy to get in quantity without raising suspicion. How long does it take? No idea.