The attack came as the Syrian Observatory for Human Rights reported that troops had executed 48 people earlier this week in a northern village, among them 10 children.
"The explosion that hit the town of Qardaha... Was caused by a suicide bomber driving a car along with another person," said the Observatory, adding that the passenger, likely an accomplice, also died in the blast.
"Two women and two soldiers were killed in the attack," said Observatory director Rami Abdel Rahman.
The attack, the first explosion to hit the heart of the western town since the outbreak of Syria's civil war in 2011, took place in the parking of Qardaha hospital.
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The outskirts of Qardaha have previously come under rocket fire, while Latakia province -- where the town is located -- has seen several rounds of heavy fighting.
A mausoleum containing the graves of President Bashar al-Assad's father and predecessor, Hafez, and brother Bassil, is located in Qardaha.
The clan has ruled Syria with an iron fist for more than 40 years.
Meanwhile, the Observatory said 10 children and 13 rebels were among 48 people executed by government forces in the northern village of Rityan earlier this week.
The killings took place after troops entered the town Tuesday, during an offensive aimed at cutting rebel supply lines to the Turkish border.
Abdel Rahman said all the dead were from six families.
"There was no resistance except in one house where a rebel opened fire at troops before being executed along with his family."