Yeah, actually.
And, like, literally EVERYTHING has an LD50 value.
For some things, the value is astronomically gargantuan, though.
Like, if you have to consume more than your body weight of a substance within thirty minutes in order for it to have a lethal effect, it's very improbable to ever happen by accident, and very difficult to make happen on purpose.
Allegedly, the LD50 for aspartame is 10,000 mg per kg of body weight
(I fucked up the math on the line that used to be here and got justly called out for it; 10,000 mg is only 10 grams. If someone weighs 60kg it would only be 600 grams which is still A LOT but not nearly what I thought it said at first)
(And that's how much to get to a fifty percent chance of dying - I don't know what the shape of the curve was leading up to this point, it could be nonlinear.)
HOWEVER, I can't recall if LD50 only accounts for acute mortality, or if it also accounts for chronic mortality; like, if it gives you a type of cancer that takes 20 years to kill you somehow, is that even known? no idea.