How green are the chemicals used as liquid fuels in the direct liquid-feed fuel cells intended to mobile, portable applications? Is there any risk of using such fuels? The present paper tries to give indications of answer to these questions while tackling the green chemistry concept, the liquid fuels (i.e. anodic oxidation, inherent hazards and renewability), the reaction products and by-products. The discussion especially focuses on green chemists' critical remarks and the green chemistry principles. Globally none of the liquid fuels appears to be green in terms of toxicity even if most could be produced from renewable raw materials. However this does not necessarily mean that the direct liquid-feed fuel cell technology is not green. The greenness of the direct liquid-feed fuel cell will also depend on its reliability and safety.