Are there any supplements I should avoid when taking an antibiotic? Are there any that may be helpful?

Answer:

Antibiotics can be affected by the supplements you take, and they can affect your ability to absorb certain vitamins and minerals.

The interactions will depend on the type of antibiotic you are taking.

Some of the most common antibiotics are listed below, followed by the supplements with which they can interact. Use the links for more details: 

Amoxicillin (Amoxil, Trimox, Wymox): Bromelain, vitamin K 

Cephalosporins (cephalexin (Cefanex, Keflex, Keftab, Biocef), cefdinir (Omnicef), etc.): Vitamin K 

Fluoroquinolones (ciprofloxacin (Cipro), levofloxacin (Levaquin)): Calcium, magnesium, iron and zinc, fennel, Dong Quai, St. John's Wort

Tetracyclines (doxycycline (Bio-Tab, Doryx, Doxy-Caps), tetracycline hydrochloride (Achromycin V, Panmycin etc.): Calcium, magnesium, iron and zinc, Dong Quai, St. John's Wort, citrate (i.e. potassium citrate)

Trimethoprim/sulfamethoxazole (Bactrim, Cotrim, Septra, Sulfatrim): Folate, PABA (para-aminobenzoic acid), potassium, white willow, St. John's wort 

Interestingly, some of the supplements noted above (folate and vitamin K) may, at times, be helpful when taking certain antibiotics, as can probiotics.