3,4-Dihydroquinazoline 1 as T-type calcium channel blocker was in vivo evaluated against A549 xenograft in BALB/c-nu Slc mice, which exhibited 54% tumor growth inhibition through oral administration of 8 mg/kg of body weight and was slightly less active than doxorubicin (68%). In addition, this compound was also profiled for its acute toxicity to ICR mice to afford oral $LD_{50}$ value of 1,038 mg/kg of body weight.