Achilles tendon pain or rupture after fluoroquionolone treatment has b
een described as an uncommon adverse effect. We report two patients wi
th ciprofloxacin-associated Achilles tendon disease,;one with histopat
hological examination. Microscopic evaluation showed irregular collage
n fiber arrangement, hypercellularity, and increased interfibrillar gl
ycosaminoglycans. These pathological features are also seen in tendon
overuse injuries in athletes.