I'm taking doxycycline for chlamydia.i dropped one tablet down the sink but took all the rest. will it still be effective?

STD: if you took the full course of doxycycline for the chlamydia, missing one pill should be OK. usually a repeat swab for chlamydia is performed after doxycycline is finished to test for cure of chlamydia infection.

Yes: If you took all the others as directed, you are doing better than 90% of people who are on this treatment. You should be fully treated. Best wishes!