Swift 3.0
do {
let attrStr = try NSAttributedString(
data: "<b><i>text</i></b>".data(using: String.Encoding.unicode, allowLossyConversion: true)!,
options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
documentAttributes: nil)
label.attributedText = attrStr
} catch let error {
}