[simrangh]

If acids are poisonous why doesn't citric acid poison you?  (please help)

[enahs]

Look into the strengths of acids and bases.

[Borek]

If acids are poisonous why doesn't citric acid poison you?  (please help)

Question asks "If acids are posionous" - they are not

This statement is so general it makes no sense. There are billions of different acids, some are dangerous, some are poisonous, some are perfectly safe.

[shelanachium]

The dangerous acids are very strong liquid ones like H2SO4 which because they avidly combine with water (in part by protonating it to H3O+, which only a very strong acid can do) damage living tissue by dehydration. HNO3 and HClO4 are similar, but even worse because they are also strongly oxidising.

Others are poisonous because the corresponding anions are. HF, quite a weak acid, is toxic because the F- ion is. Same goes for HCN, a very weak acid indeed.

One of the very strongest acids known, HCB11Cl12, is quite harmless because it is an involatile solid that just 'sits there' and the anion is non-toxic.(look up 'carborane superacids' on the Web.)

Citric acid is also an involatile solid with a non-toxic anion (indeed an essential component of life); but is also a weak acid.

[Borek]

The dangerous acids are very strong liquid ones like H2SO4

It depends on their concentration. Just because an acid is strong doesn't make it dangerous. Being strong and concentrated is another thing.

Citric acid is also an involatile solid

With good water solubility.

[AWK]

The dangerous acids are very strong liquid ones

People suffered from insufficient stomach acidity even drink a diluted HCl