(Reuters) - Baidu Inc <BIDU.O>, China's largest Internet search company, posted its steepest-ever quarterly profit decline and slowest growth in revenue in nearly eight years, hit by a healthcare scandal that ensnared the company this year.

Public uproar has hounded Baidu after a student suffering from a fatal form of cancer blamed the company for directing him to suspect and ultimately ineffectual treatment.

Regulators responded by slapping curbs on the firm's lucrative healthcare advertising business, spurring Baidu to lower its revenue forecasts for the second quarter.

The company said it expects third-quarter revenue of 18.04 billion yuan-18.58 billion yuan ($2.71 billion-$2.79 billion) representing a decrease of 1.9 percent to an increase of 1.1 percent, year-over-year.

Last week, regulators said they were once again investigating Baidu, this time over reports that illegal gambling websites used the search engine to promote themselves. Additional punishment could further jeopardize the company's prospects.

Baidu's net income fell to 2.41 billion yuan ($362 million) in the April-June quarter from 3.66 billion yuan a year earlier, Baidu said in a statement on Thursday.

The company was expected to post net income of 2.42 billion yuan, according to a Thomson Reuters survey of eight analysts.

Baidu's revenue rose 10.2 percent to 18.26 billion yuan from 16.58 billion yuan a year earlier, marking its slowest growth in nearly eight years. Analysts on average estimated revenue of 18.18 billion yuan.

Shares of the company, which were down marginally in extended trading, have fallen 12.4 percent since the beginning of the year.

(Reporting by Siddharth Cavale in Bengaluru; Editing by Saumyadeb Chakrabarty)