Patch-use behavior can be influenced by parasitism risk and individual condition. Recent evidence suggests that hosts may avoid foraging in a patch contaminated with feces, potentially to avoid parasite infection. We examined whether wild Formosan mice, Apodemus semotus, alter patch-use behavior in response to parasite removal treatment and level of parasitism risk associated with a patch. We live-trapped the mice and marked them with passive integrated transponder tags. Half of all captured adult mice were treated with ivermectin to remove their helminth parasites. We set up food stations consisting of three patches: (1) food contaminated with feces that have high numbers of parasite eggs; (2) food contaminated with feces that have low numbers of parasite eggs; and (3) food not contaminated with feces. A data logger and a PIT antenna were attached to each patch to record the time an individual mouse spent in that patch. We found that the mice treated with ivermectin spent less time in the two patches contaminated with feces than the clean patch. In contract, the mice that were not treated with ivermectin spent equal amount of time among the three patches. Our results suggest that wild mice with lower parasite infection show increased risk sensitivity in patch-use behavior when foraging.