Swiss pharmaceutical firm Novartis said Sunday it was recalling four different products sold over the counter in the United States over reports of a malfunction at one of its plants. The affected drugs are Excedrin, NoDoz, Bufferin and Gas-X Prevention, Novartis Consumer Health (NCH) said in a statement. \"NCH is taking this action as a precautionary measure, because the products may contain stray tablets, capsules, or caplets from other Novartis products, or contain broken or chipped tablets,\" it said. \"Mixing of different products in the same bottle could result in consumers taking the incorrect product and receiving a higher or lower strength than intended or receiving an unintended ingredient. \"This could potentially result in overdose, interaction with other medications a consumer may be taking, or an allergic reaction if the consumer is allergic to the unintended ingredient,\" the statement said. The group stressed however that it was not aware of adverse effects among the affected products\' consumers. The plant in Lincoln, Nebraska where the products are manufactured was shut down last month and Novartis said improvements were being carried out there.