What to do if i swallowed methylene blue accidently?

Seek medical advise: seek medical advise if you have any symptoms as Anxiety, Weakness, Headache, Lightheadedness or difficulty breathing Also seek medical advise if you have preexisting medical conditions, or ingestion of more that 35 mg / kg body weight, also in all injections greater than the recommended dose, or eye/ skin contact that is causing irritation

It depends almost: entirely on the dose you took, altho certain factors like what other medications you're taking and what else is in the methylene blue, are also important. Most important: Don't rely on a Google search for an answer. Contact poison control immediately @ 800-222-1222. Tell them approximate amount you ingested, the form it's in and your medication list and take their advice!