The Easy Rider actor has now cancelled all his travel plans as he focuses on getting treatment through a special programme at the University of Southern California.
His manager Sam Maydew added: Were hoping for the best.
The 73-year-old star had to cancel an appearance at Melbourne’s Australian Centre for the Moving Image, where a collection of his artwork and photography Dennis Hopper and the New Hollywood is being shown.
Last month, Dennis was released from a New York hospital after being treated for dehydration.
It was initially reported the 73-year-old star was suffering from flu-like symptoms, but further details of his illness were not been released.
Dennis fell ill in New York while promoting his new TV series 'Crash', which is based on the 2004 Oscar-winning movie about racial and social tensions in Los Angeles of the same name. He plays music producer Ben Cendars.
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