This review summarizes the essential medicinal chemistry of curcumin, focusing on its bioactivity, covalent modifications, and potential toxic side effects. Curcumin is a polyphenolic compound derived from turmeric with a wide range of biological activities. It has been shown to covalently modify several proteins, including TrxR (thioredoxin reductase), IRAK (interleukin-1 receptor-associated kinase), and ErbB2 (Her2/neu). These modifications can lead to changes in enzyme activity, such as increased NADPH oxidase activity and ROS production, which may have therapeutic implications in cancer treatment. Curcumin also exhibits anti-inflammatory properties by inhibiting IRAK recruitment to the IL-1 receptor, thereby blocking inflammatory signaling. In addition, curcumin can induce the ubiquitination and degradation of ErbB2 through the Michael reaction, which may contribute to its anti-cancer effects. However, curcumin's potential toxic side effects, such as its impact on cytochrome P450 and glutathione S-transferase activities, must be considered. The half-life of curcumin varies depending on the conditions, and its stability in buffer solutions is an important factor in its bioavailability. Curcumin also interacts with glutathione and may affect iron status when consumed long-term. Despite these considerations, curcumin remains a promising candidate for further research and development in medicinal chemistry due to its diverse biological activities and potential therapeutic applications.This review summarizes the essential medicinal chemistry of curcumin, focusing on its bioactivity, covalent modifications, and potential toxic side effects. Curcumin is a polyphenolic compound derived from turmeric with a wide range of biological activities. It has been shown to covalently modify several proteins, including TrxR (thioredoxin reductase), IRAK (interleukin-1 receptor-associated kinase), and ErbB2 (Her2/neu). These modifications can lead to changes in enzyme activity, such as increased NADPH oxidase activity and ROS production, which may have therapeutic implications in cancer treatment. Curcumin also exhibits anti-inflammatory properties by inhibiting IRAK recruitment to the IL-1 receptor, thereby blocking inflammatory signaling. In addition, curcumin can induce the ubiquitination and degradation of ErbB2 through the Michael reaction, which may contribute to its anti-cancer effects. However, curcumin's potential toxic side effects, such as its impact on cytochrome P450 and glutathione S-transferase activities, must be considered. The half-life of curcumin varies depending on the conditions, and its stability in buffer solutions is an important factor in its bioavailability. Curcumin also interacts with glutathione and may affect iron status when consumed long-term. Despite these considerations, curcumin remains a promising candidate for further research and development in medicinal chemistry due to its diverse biological activities and potential therapeutic applications.