茄碱（Solanine），又称龙葵碱、茄苷，是一种有毒的甾族生物碱苷类化合物，由 β-D-葡萄糖、D-半乳糖和 L-鼠李糖组成的茄三糖与茄啶相连组成。

存在于马铃薯、番茄和茄子等茄科植物中。α-茄碱与α-卡茄碱占马铃薯中总糖苷生物碱含量的95％。马铃薯中茄碱的含量一般为 30～100mg/kg，通常认为 200mg/kg 以内食用是安全的，但发芽马铃薯芽眼四周和见光变绿部位，茄碱的含量极高，可达 5g/kg，因此食用是非常危险的。

1820年首先由 Desfosses 从茄科植物龙葵（Solanum nigrum）的浆果中分离得到，因此得名。

Solanine is a glycoalkaloid poison found in species of the nightshade family (Solanaceae), such as the potato (Solanum tuberosum), the tomato (Solanum lycopersicum), and the eggplant. It can occur naturally in any part of the plant, including the leaves, fruit, and tubers. Solanine has pesticidal properties, and it is one of the plant's natural defenses. Solanine was first isolated in 1820 from the berries of the European black nightshade (Solanum nigrum), after which it was named.