Why might Odysseus be so opposed to eating the lotus fruit?

Odysseus was opposed to eating Lotus because of the medicinal effects of the plant. The lotus tree's fruit can cause drowsiness and lethargy. Odysseus needed to be alert in order to complete his tasks. His refusal of the lotus fruit is due to his awareness of its negative effects. The plant is also addictive.

Interestingly, there was an island civilization near North Africa that consumed only the lotus fruit. They were called "lotophagi".