Lana Sue Clayton is also charged with unlawful malicious tampering of food between the dates of July 19 and July 21, York County investigators said
Officials said Clayton's husband, Stephen Clayton, died July 21 from poisoning.
They said the crime occurred at the couple’s home in Clover.
"It just makes no sense,” said Deborah Pollard, who lives nearby.
Authorities said toxicology tests found poisonous levels of tetrahydrozoline -- the chemical found in eye drops -- in Stephen Clayton's body.
"Somebody does something like that? That's crazy,” said Sean Magan, another neighbor.
They said Lana Clayton admitted to giving her husband the substance without his knowledge.
"That's crazy,” Pollard said. “They're just finding all kinds of ways to do crazy things nowadays, aren't they?"
Lana Clayton was booked into the York County Detention Center.
Neighbors said the Claytons were married for eight years.
One woman said Lana Clayton attended a neighborhood Bible study and Stephen Clayton was known for his big personality.
Neighbors said Stephen Clayton’s funeral was held earlier this month in the backyard of their home before detectives determined his cause of death.