The first incident occurred around 9:50 a.m. near Aurora and Wickham roads.
According to Melbourne police, callers reported seeing a man hiding behind trees and then running back and forth through traffic.
"He's tripping on drugs or something," a nearby business owner told 911. "Now he's lying down under the tree under the bushes on some mulch."
[LISTEN BELOW: 911 calls made in Flakka cases]
Officers approached the man, who was combative and resisted attempts to restrain him, police said.
The officers eventually placed the man into protective custody, and he was taken to a hospital, police said.
The second incident occurred around 12:50 p.m. at the Melbourne Regional Medical Center at 250 N. Wickham Road.
Police said the man was acting erratically in the emergency room and was disruptive with hospital staff.
Officers arrived as the man's behavior escalated and he acted out physically toward the staff, according to police.
Police said the man yelled that he would never do drugs again, and he told officers that he had taken heroin laced with Flakka.
Melbourne police said it's not known if the men knew each other or obtained their drugs from the same source.
"However, the department wants the community to be aware of these incidents as these drugs create a public safety risk and are dangerous," police said in a news release. "Erratic and sometimes violent behavior is a serious side effect to synthetic or hallucinogenic drug abuse."
Police said anyone who comes in contact with someone acting erratically is urged to call police.
"Avoid interacting with these subjects as their actions can be unpredictable," police said. "Often, friends and family members of these individuals are surprised by their behaviors and describe the person as normally passive or nonviolent. These individuals are likely suffering a medical emergency which without treatment can be life-threatening."