This study investigated startle reflex modulation in 33 healthy student participants during the processing of negated emotional items. To build upon previous research, our particular interest was to find out whether processing of negated emotional items modulates emotional responding in line with the logical meaning of the negated expression, or instead leads to paradox emotional effects that point in the direction opposite the one logically implied by the negation. Startle reflex modulation was assessed during silent reading of pleasant and unpleasant nouns. The nouns were either paired with the possessive pronoun my or with the negation word no. The startle eyeblink amplitude was enhanced during processing of the unpleasant pronoun–noun phrases and attenuated during processing of the pleasant phrases. Negation attenuated the startle eyeblink for negated unpleasant nouns and enhanced it for negated pleasant nouns. In line with this finding, negation decreased arousal ratings for unpleasant nouns and reversed the valence ratings for pleasant nouns. Our results are the first to show an effect of negation on both peripheral physiological and subjective indices of affective responding, which suggests that negation may be an effective strategy for spontaneous down-regulation of emotional responses to unpleasant, but not to pleasant, stimuli.