Caffeinated drinks (coffee, energy drinks) and tonics combination notes: ① limited intake (1–2 cups daily): little impact on effects, ② excessive intake (3+ cups): can interfere with herbs (especially heart-calming herbs), ③ before tonics taken: avoid taking together (1–2 hour gap recommended), ④ pre-exam: wean off caffeine to maintain natural concentration. Caffeine causes sleep disturbance, anxiety, and palpitations side effects, so reduction is recommended.