Can taking hCG give me a false pregnancy result?

Possibly, it depends. Injected HCG such as used for fertility treatments can absolutely give you a false positive on a serum or a urine test within a certain time period. Taking HCG by mouth, which I've seen with the 'hcg diet' is unlikely to show up on a test.
Yes. The urine dipstick tests for HCG so taking it will give a false positive result.

Related Questions

Could I be pregnant or is it a false pregnancy? I had hCG shot and now my test is slightly positive.

Either one depending. Hcg injection stays in the body for an average of 10 days. Checking a pregnancy test prior to that time can give a false positive, while checking much after 10 days is usually due to pregnancy if the test is positive. I hope this helps!

Is a negative hCG level a true test for determining a false pregnancy?

Unclear. Not sure what is meant by a false pregnancy (molar pregnancy, blighted ovum, HCG cross reactivity).
Maybe. A truly negative HCG test result (that can be confirmed on a blood test a few days later) means a person was not pregnant. Whether or not she has a false pregnancy depends on her other signs and symptoms.