An intravenous drip assembly comprises a fluid container - i.e. a saline bag - a drip chamber 3 and a sensor 1 arranged to clamp onto or over the drip chamber 3 to monitor its fluid level. The sensor 1 is preferably provided as a refracted light sensor making use of a photosensitive emitter and receiver, or an ultrasonic level sensor making use of an ultrasonic emitter and receiver. The sensor 1 further preferably makes use of a flexible attachment or closure mechanism 4 to allow for its attachment to a wide array of drip chambers 3. A remote alert device (200, Fig 7a) for alerting a user to anomalous flow conditions may also be provided. It is also taught in the application that a secondary fluid container preferably a syringe (30, Fig 12) or a secondary drip chamber (333, Fig 14) may be included in the IV line. The secondary fluid container providing a secondary, emergency supply of fluid； thus ensuring that a constant supply of fluid is available to the patient when the primary fluid container is being replaced.
