Nurse!

QVC guest host Cassie Slane experienced an on-air medical emergency yesterday on live TV -- clutching her chest and collapsing on her co-host -- but thankfully, she's doing much better now.

Cassie and co-host Dan Hughes were hocking tablet devices for kids on the show "Sundays with Carolyn and Dan" when Cassie suddenly looked ill and fell over, appearing to faint.

The camera immediately cut away -- but Dan kept pitching the product, presumably while Cassie received some kind of medical attention.

Cassie returned to the camera moments later to pick up right where she left off ... but a few seconds in, she started slurring her words. The camera cut again and Dan finally said, "Cassie's having a little problem."

It's unclear what went wrong -- but Cassie took to Twitter hours ago, saying, "Thanks everyone for the well wishes. Feeling better today."

FYI -- it's not the first time Cassie has collapsed on air --a similar incident occurred during an electronics segment in 2010.

Cops and firefighters rushed to the L.A. home of Playboy model Kendra Wilkinson this week ... after her 2-year-old son mysteriously passed out -- TMZ has learned.

Law enforcement sources tell us, authorities responded to a 911 call from Kendra's home this Wednesday around 5:00 PM -- and when they arrived, her son Hank Baskett IV was just coming to.

We're told the son was transported to a nearby hospital for medical attention, and released shortly after.

According to sources, the doctor told Kendra her son had suffered loss of consciousness due to overheating ... from running around the house ... and it's pretty common in children, especially in hot weather.

Mike Tyson tells TMZ he "feels great" following a recent neck surgery ... and despite the gnarly scar on his neck, Mike says he should be back to normal in just 3 weeks.

Tyson turned heads (not his own) when he showed up to a media event in Vegas this weekend sporting a neck brace. The former champ reportedly had titanium pins put in his neck to add support to a degenerative disk.

Tyson's rep tells us, "Its a very common surgery, especially for athletes."

The rep adds, "He feels great ... just has to wear the neck brace to keep everything stable for the next 3 weeks.”

Here it is ... straight from Justin Bieber's mouth ... a full explanation why the pop superstar heaved his guts out on stage at a concert this weekend -- and it all comes down to moo juice.

Bieber just called in to "TMZ Live" and said he had been throwing down whole milk and spaghetti bolognese right before his concert in Phoenix on Saturday ... and it turned his guts into a ticking puke bomb.

Indianapolis Colts head coach Chuck Pagano has been diagnosed with a treatable form of leukemia, the team announced today, and will miss several games to receive treatment.

Colts owner Jim Irsay made the announcement at a news conference today, saying, "He is ready to take this fight on and he is a fighter."

Pagano, 51, had been experiencing what he believed to be fatigue, but a blood test revealed he was suffering from leukemia. He has been receiving treatment in the intensive care unit at an Indianapolis-area hospital since Wednesday.

Bruce Arians, the team's offensive coordinator, will serve as the interim coach in Pagano's absence.

***Be careful watching this video if you have a weak stomach.***

Justin Bieber must have come down with a real severe case of Bieber Fever last night in Glendale, AZ ... because in the middle of his concert ... he PUKED ON STAGE!!!

The show was the first on his new "Believe" tour and even though he was forced to leave the stage twice due to illness, the show went on.

Spider-Man, Bruce Banner, Daredevil, The Avengers and the X-Men can all rest easy ... 'cause their fearless creator Stan Lee is alive and kickin' after getting a pacemaker implanted near his heart.

The 90-year-old comic book legend just fired off an AWESOME statement to fans after undergoing pacemaker surgery in L.A. last week, in which he proudly declares that he's not yet ready to become the Grimm Reaper's bitch:

"Attention, Troops!

This is a dispatch sent from your beloved Generalissimo, directly from the center of Hollywood’s combat zone!

Now hear this! Your leader hath not deserted thee! In an effort to be more like my fellow Avenger, Tony Stark, I have had an electronic pace-maker placed near my heart to insure that I’ll be able to lead thee for another 90 years.

Bam Margera says his herpes sore is GONE following his crazy run-in with a naked, masturbating female intruder ... and tells us he only wants to see the woman get help.

As TMZ first reported, Margera claims he woke up in the middle of the night to find a woman trying to kiss him, and when he went to call police ... she laid on the floor and started masturbating.

Bam claimed a cold sore sprouted on his mouth following the incident -- and believes it's the result of direct contact with the woman (ew!!!) or from the stress of the whole thing. But last night in Hollywood, Bam recounted the ordeal for us and gave us the good news ... his cold sore has cleared up.

Bam says he's not interested in pressing charges and just wants to see the woman get help.

Here comes Sugar Bear Mike! Honey Boo Boo's papa is finally back home tonight after 12 grueling days of hospital treatment for a nasty leg infection.

Sugar was hospitalized almost 2 weeks ago after a leg injury he suffered on his ATV took a turn for the worse ... and required emergency surgery.

Even though he's on the mend, Sugar still needed one of his buddies to carry him up the front stoop at home in McIntyre, GA.

Mama June and the kids all came out to greet Sugar at the door.

Bam Margera is convinced the naked chick who broke into his house and masturbated on his floor ... might have left a little gift behind as well -- HERPES.

Bam and his friend Tony Hawk posted a video on YouTube ... where Bam tells Tony everything that went down the night his alleged stalker was arrested two weeks ago -- including the part where she pleasured herself in front of him.

But then the "Jackass" star drops a bombshell -- he says he woke up the day after she busted in with a giant sore on his bottom lip.

The nut-smashing "America's Got Talent" star who became famous for abusing his testicles on TV was seriously injured in a stunt-gone-wrong ... suffering several broken bones and a soiled pair of underpants, TMZ has learned.

The man at the center of the painful situation appeared on the show as "The Horse" -- real name Zac Gordon.

Gordon tells us he was filming a stunt last weekend with some of his "AGT" buddies in which he was supposed to jump from a two-story roof and land crotch-first on a wooden plank.

In the video ... you see Horse hit the plank -- but he says he ultimately landed on a bucket of cement that was being used to hold the wood in place.

Horse tells us the impact was so intense ... he broke several ribs and defecated in his shorts upon impact.

The amateur daredevil says he refused to go to the hospital ... but consulted with a doctor afterward just to be safe.

Lindsay Lohan believes getting arrested is bad for her health ... 'cause she's telling friends the stress from her NYC bust aggravated her pre-existing pneumonia so badly, she had to be hospitalized.

We broke the story .. Lohan was rushed to the emergency room in NYC Sunday night with a lung infection ... but was released a short time later.

Now, Lindsay's telling friends the arrest caused her so much anxiety, it landed her in the hospital -- exacerbating the "walking pneumonia" she's been suffering from the last few weeks.

That's right, Lindsay is blaming stress for her damaged lungs ... Lindsay, the infamous chain smoker who blew through 49 packs of cigarettes in 47 days while she stayed at the Chateau Marmont this summer.

Lindsay Lohan was rushed to the emergency room in NYC last night ... and sources connected to the actress tell us she's suffering from a bad lung infection.

Lindsay has been telling friends she's been dealing with a bad case of "walking pneumonia" for the last couple weeks -- and last night, we're told things got so bad she had to go to the hospital.

We're told Lindsay was taken to Mt. Sinai, where she received medication for the infection -- including antibiotics -- and was discharged shortly after.

Sharon Stone was hospitalized in Italy after suffering a medical scare ... but has been released with a clean bill of health.

The actress was at a runway show in Milan on Friday, when she began complaining of severe headaches. The complaint was not taken lightly -- in 2001 Stone was hospitalized with a brain aneurysm after experiencing similar symptoms.

Stone was taken to a hospital where doctors checked her out ... releasing her in time for an Aids Research fundraiser Saturday (above).

Ann Romney's plane was forced to make an emergency landing in Colorado moments ago ... after a fire broke out in the cockpit and the cabin filled with smoke.

According to a Romney spokesperson, the plane landed safely and no one onboard suffered any injuries.

The rep posted a statement on Twitter saying, "All okay. Thank goodness."

Upon arrival, the fire department rushed to the plane in an effort to find the source of the smoke. A spokesperson for the Denver Fire Dept. said the smoke came from a "small fire in the cockpit."

The plane was heading from Omaha to Los Angeles.

Honey Boo Boo's daddy Sugar Bear required emergency surgery to treat a nasty infection in a leg wound he suffered during a freak ATV accident last week -- but doctors will NOT have to amputate ... this according to Mama June.

TMZ broke the story ... Sugar Bear sustained the leg injury while mud boggin' -- which is a fancy term for redneck off-roading. He was pictured on crutches following the injury ... but the wound got so infected that he needed to be hospitalized.

Mama June tells TMZ ... doctors decided to perform a debridement -- a surgical procedure to remove infected tissue from the body so it can heal properly.

Mama June, Honey Boo Boo and the rest of the family visited Sugar Bear after the procedure and said he is in good spirits and craving some peanut butter crackers.

June tells TMZ ... doctors expect Sugar Bear to make a full recovery ... and he should be clear to return to work in 4 weeks.

There was talk that Sugar Bear's infection was so bad, docs would have to remove parts of the leg via amputation ... but June says the rumors are "100 percent not true."