Aktiviti antioksidan dan antikulat sebelas spesies kayu keras dagangan Malaysia daripada tujuh keluarga berlainan telah dikaji. Ekstrak metanol bahagian kulit, kayu teras dan kayu gubal daripada setiap spesies telah diuji menggunakan 1,1’-difenil-2- pikrilhidrazil (DPPH) untuk penentuan aktiviti antioksidan. Kandungan fenolik pula telah dinilai dengan menggunakan kaedah Folin-Ciocalteau. Ekstrak yang diuji daripada bahagian kulit Angsana, kulit dan kayu gubal Keruing latek, ketiga-tiga bahagian Kekatong, merpauh periang, kulit dan kayu gubal Bintangor bukit, dan kulit Sentul telah menunjukkan aktiviti antioksidan. Bahagian kulit Bintangor bukit telah dipecahkan lebih lanjut oleh kaedah kromatografi iaitu kolum kromatografi (CC) dan cecair-cecair (pembahagian) kromatografi (LLC). Catechol di samping beberapa sebatian lain seperti fenol, syringol, guaiacol dan 4-metilcatechol, telah dikenal pasti oleh pirolisis gas kromatogram jisim spektrometer (Py-GC/MS) sebagai sebatian yang paling penting bagi bahagian kulit Bintangor bukit untuk menyingkirkan radikal bebas. Antioxidant and antifungal activities of eleven hardwood species of Malaysian commercial timbers from seven families were studied. Methanolic extracts from bark, heartwood and sapwood of each species were subjected to 1,1’-diphenyl-2-picrylhydrazyl (DPPH) for the antioxidant activity determination. Total phenolics were evaluated using the Folin-Ciocalteau method. The tested extracts of Angsana bark, Keruing latek bark and sapwood, all three parts of Kekatong, Merpauh periang bark, Bintangor bukit bark and sapwood, and Sentul bark did showed antioxidant activity. Bintangor bukit bark was further fractionated by column chromatography (CC) and liquid-liquid (partition) chromatography (LLC). Catechol with a few other compounds such as phenol, syringol, guaiacol and 4-methylcatechol were detected by pyrolysis gas chromatography mass spectrometry (Py-GC/MS) as the most important compounds responsible for Bintangor bukit bark to scavenge the free radicals.