Acute prosthetic heart valve thrombosis (PHVT) is a severe complication affecting patients who have undergone heart valve replacement surgery. We present a case of acute recurrent PHVT associated with parasite-induced eosinophilia. A man in his early 50s with rheumatic heart disease underwent mechanical mitral valve replacement 5 years ago and received well-managed anticoagulation with regular follow-up visits. The patient developed a sudden onset of dyspnoea and was diagnosed with mechanical valve thrombosis, which was managed with thrombolysis. However, the valve became stuck again just a week after the initial episode while the patient was still in the hospital and was receiving anticoagulation within the target range. Concurrently, he experienced skin rashes and itching, prompting an investigation that revealed hypereosinophilia secondary to parasite infestation. The patient's valve functions well after thrombolysis and parasite infection treatment. The eosinophil counts were monitored to remain within the normal range.