Welcome to HCM
I would like to tell you that bleeding gums
are symptom of gingivitis
To get its complete cure you need to go for oral prophylaxis.
Still if you want to know medication then doxycycline 100 mg twice a day can be taken for 5 days, but avoid taking it with food & its contraindicated in pregnancy
& nursing mother.
You can also go for metronidazole-400mg twice a day for 5 days.