The multiplex coherent anti-Stokes Raman scattering microscopy allowed label-free visualization of cytoplasmic lipid droplets (LDs). The LDs, which act to conserve energy storage, are usually accumulated during the normal apoptosis of HeLa cells with activation of caspase-3/7 leading to downregulation of the fatty acid catabolism pathways. During cultivating in nonthermal plasma-activated medium (PAM), while the activation of caspase-3/7 was induced, the authors found that a dynamic exhaustion of the intracellular LDs, underlying the metabolic mechanism of the PAM-induced apoptotic cell death of HeLa cells.