<![CDATA[Abstract. Herbal medicine is widely used by the Indonesian community; however, products illegally adulterated with medicinal chemical substances, such as paracetamol and dexamethasone, are still found on the market, posing potential health risks. This study aimed to detect the presence and determine the levels of paracetamol and dexamethasone in jamu marketed for the treatment of chikungunya in Indramayu Regency. This laboratory experimental study used six samples selected through purposive sampling. Qualitative analysis was performed using Thin-Layer Chromatography (TLC), while quantitative analysis was carried out using High-Performance Liquid Chromatography (HPLC). Method validation included system suitability, specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). TLC analysis showed that samples A, B, D, and F were positive for paracetamol, with Rf values of 0.40, 0.34, and 0.43, whereas dexamethasone was not detected. Method validation showed system suitability %RSD values of 0.731% for paracetamol and 0.68% for dexamethasone, coefficient of determination (R²) values of 0.993 and 0.996, and precision (%RSD) values of 0.76% and 0.729%, respectively. The accuracy parameter did not meet the acceptable range of 98–102%, and the LOD and LOQ parameters also failed to meet the validation criteria. Based on the findings, several jamu products marketed for the treatment of chikungunya were found to contain paracetamol and dexamethasone as medicinal chemical substances. Abstrak. Jamu merupakan obat tradisional yang banyak digunakan masyarakat, namun masih ditemukan produk yang secara ilegal mengandung bahan kimia obat, seperti parasetamol dan deksametason, yang berpotensi menimbulkan risiko kesehatan. Penelitian ini bertujuan mendeteksi keberadaan serta menetapkan kadar parasetamol dan deksametason pada jamu dengan klaim pengobatan chikungunya yang beredar di Kabupaten Indramayu. Penelitian eksperimental laboratorium ini menggunakan enam sampel yang dipilih secara purposive sampling. Analisis kualitatif dilakukan dengan Kromatografi Lapis Tipis (KLT), sedangkan analisis kuantitatif menggunakan Kromatografi Cair Kinerja Tinggi (KCKT). Validasi metode meliputi uji kesesuaian sistem, spesifisitas, linearitas, akurasi, presisi, batas deteksi (LOD), dan batas kuantifikasi (LOQ). Hasil KLT menunjukkan sampel A, B, D, dan F positif mengandung parasetamol dengan nilai Rf 0,40; 0,34; dan 0,43, sedangkan deksametason tidak terdeteksi. Hasil validasi menunjukkan nilai %RSD kesesuaian sistem sebesar 0,731% untuk parasetamol dan 0,68% untuk deksametason, nilai R² masing-masing 0,993 dan 0,996, serta nilai presisi (%RSD) 0,76% dan 0,729%. Parameter akurasi belum memenuhi rentang 98–102%, demikian pula LOD dan LOQ. Berdasarkan hasil penelitian, beberapa sampel jamu chikungunya terbukti mengandung parasetamol dan deksametason sebagai bahan kimia obat.]]>
