Background: Plumbago indica Linn. and its active constituent, plumbagin, are conventionally used in Thai alternative medicines, but information regarding their effects on cytochrome P450 (CYP450) enzymes is limited. Objective: To establish the effects of P. indica Linn. and plumbagin on CYP450 profiles. Materials and Methods: Adult male mice were orally administered P. indica extract (20, 200, and 1000 mg/kg/day) or plumbagin (1, 5, and 15 mg/kg/day) for 14 days. The levels of hepatic CYP450 mRNA and protein were assessed using reverse transcription/real-time polymerase chain reaction and immunoblotting, respectively, and specific enzyme reactions were performed to determine the enzyme activities. Results: Expression of Cyp1a2 was induced by both P. indica and plumbagin, while P. indica, but not plumbagin, slightly suppressed Cyp2c29 expression. Expression of Cyp2d9 was suppressed by both P. indica and plumbagin. Expression of Cyp2e1 was unchanged, but P. indica at the lowest dose increased Cyp2e1 activity. P. indica and plumbagin dose-dependently suppressed the expression of Cyp3a11/13 and its activity. Conclusions: Modulation of CYP450 profiles by P. indica and plumbagin is a concern as there are risks of drug–herb interaction.