Possible Clues:

• Man on board so ill takes small dose of aperient salt
• Crown-wearer thus, filling rotten, requiring a compound present in toothpaste
• Sodium bicarbonate
• What banker does without mid-morning drink for a rise
• Ingredient in some tooth whiteners
• Flexible bag is OK and gets used in the kitchen
• Antacid compound
• Common name for sodium bicarbonate
• Common antacid
• Foreign high-flyers join sovereign's Repeal Party with anonymous agent involved in The Rising