i wouldnt bother taking it

There are tales all over the place about people gradually building up immunity to poisons by starting with very weak diluted doses and gradually building up the strength of them. Nero's mother supposedly did that, so when he poisoned her, it didn't kill her. In China, some men are said to soak their hands in gradually increasing doses of poison until the hand becomes poison. This poison is said to penetrate skin upon contact, so they have a Touch of Death=Poison Hand! I haven't tried any of that, so I don't know if it works or not.

"It is important to note that mithridatism is not effective against all types of poison (immunity generally is only possible with biologically complex types which the immune system can respond to) and, depending on the toxin, the practice can lead to the lethal accumulation of a poison in the body. Results depend on how each poison is processed by the body, ie, on how the toxic compound is metabolized or passed out of the body. In some cases, it is possible to build up tolerance against specific non-biological poisons. For some poisons, this involves conditioning the liver to produce more of the particular enzymes that deal with these poisons (for example alcohol). Another mechanism involves conditioning the target tissues of the poisons. These methods do not work for all non-biological poisons. Exposure to certain toxic substances, such as hydrofluoric acid and heavy metals, is either lethal or has little to no effect, and thus cannot be used in this way at all. Arsenic is a notable exception with some people actually having a genetic adaptation granting them higher resistance which can be replicated with mithridatism.[7] In addition, simple toxins that work through chemical processes that bypass the immune system cannot be dealt with (good example would be the variants of cyanide). There are only a few, if any, practical uses of mithridatism. Venomous snake handler Bill Haast used this method. Snake handlers from Burma are said to tattoo themselves with snake venom for the same reason.[8]" https://en.wikipedia.org/wiki/Mithridatism

Roman legends of Mithradates of Pontus should not be taken as medical fact.

No. You're confusing drug tolerance with tissue degradation. Venom/poisons don't just make you sick short term, they also damage the tissue and organs long term. It's why smokers and alcoholics don't "get stronger" as they take on bigger doses. . .