Clam Shell — Safety & Interactions

Hai Ge Ke · Concha Cyclinae

Contraindications

  • Cold-deficiency cough or wheezing with thin clear sputum
  • Deficiency-cold digestion without heat, phlegm, nodules, or hyperacidity

Cautions

  • Medication spacing matters because calcium-rich shell powders can interfere with absorption of some oral drugs.
  • Source quality and proper cleaning are important for shell medicines, especially when powders are being used internally.
  • Calcined and raw forms should not be treated as identical, because processing changes shell chemistry and traditional therapeutic emphasis.

Drug Interactions

Drug Class / Substrate Mechanism Severity Source
Fluoroquinolone antibiotics - shell calcium can reduce absorption; separate dosing
Tetracycline antibiotics - chelation may reduce drug availability; stagger use
Levothyroxine - calcium-containing shell products may impair absorption; separate by at least 4 hours
Iron supplements - calcium can reduce iron absorption when taken together

This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before using herbal medicines, especially if you take prescription medications.