Hillary Clinton can't stop coughing.

*cough*

As Clinton campaigns across the country, she is followed by a persistent cough. At several rallies and speeches, Clinton was interrupted by a chronic and troublesome cough that often left her voice hoarse.

*cough*

This campaign has forced Clinton to give numerous speeches where she tends to shout. It is possible that the constant shouting could be the cause for Clinton's persistent cough.

*cough*

Some voters have expressed concern over the status of Clinton's health. During a campaign event in Iowa, a woman confronted Clinton about her health. Clinton addressed the woman's concern.

"I'll match my endurance against anybody," Clinton said. "And last spring, my doctor put out a letter and you know, said what great health."

*cough*

This isn't the first time Clinton's health has been a concern. Back in 2012, Clinton suffered a blood clot and was treated with blood thinners. The blood clot was discovered after Clinton sustained a concussion. Clinton received the concussion after she fainted. Clinton fainted because she was dehydrated. Clinton was dehydrated because she had a stomach virus.

Clinton's doctors have said they expect Clinton to make a full recovery from the blood clot.

*cough*

Another possible explanation for Clinton's consistent cough is she's simply mimicking her favorite Pokémon Koffing.