Solid state chemistry Boric acid toxicity

as far as I know, boric acid and borax are practically harmless to humans

nevertheless, they also have toxicity, like many substances

_{Wonder if it can be something to do with electeophylicity} 

@chaoticgood what do you mean by electeophylicity ?

@argentum Oh, sorry, I've meant electrophility. English isn't my first language 

@chaoticgood Okay, usually the toxicity of compounds is directly related to the ability to dissolve and be absorbed with water in the digestive tract.

Not only solubility plays important role in the process, reactivity is important too

@chaoticgood Reactivity is also related to solubility

It's tough to argue with that, but also they are two different properties of substance 

@chaoticgood Usually, for oral exposure to the body, a dependence is drawn out that the greater the solubility, the greater the toxicity, and vice versa. Remember, for example, soluble barium salts are toxic, but BaSO₄ is safe

I'm not against this statement. My idea is that it's not the only parameter 

@chaoticgood What other parameters should be considered for example?

There is more (w/w%) boron in boric acid than in borax. The form is pretty the same, B(iii) neighboured by oxygen, so only the mass fraction is matter.