The metabolic process of chiral drugs plays a significant role in clinics and in research on drugs. Here, we experimentally demonstrate by all-optical means that the chiral molecules can be quickly discriminated and monitored with the ultrahigh-order modes excited in a metal cladding optofluidic chip, achieving over 5 times sensitivity with a low-dosage sample. We show that the varying concentration of the chiral drugs can be monitored both in cell and animal experiments, presenting a significant difference between chiral enantiomers at the optimal function time and the effect of the reaction. To our knowledge, this approach provides a new way to achieve important chiral discrimination for the pharmacokinetics and the pharmacodynamics and may present opportunities in indicating the health status of humans.