Take two goblins before breakfast with water...

'You're overworked,' said Doctor Melchitt in grave tones. 'You need to get get some better brownies. Have you checked to see if the ones you have have --' and here he lowered his voice and continued in a conspiratorial whisper '-- communist sympathies?'
'I think my brownies are entirely normal, Doctor,' I said meekly. Doctor Melchitt had long grey sideburns that cascaded down his face and fell off the bottom of his jaw and deep-set eyes that were so shadowed by his brow that I've never managed to make out their colour. He scared me, with his authoratative manner and huge, huge hands that palpated and prodded and made me squirm.
'You should check anyway,' he said. 'Perhaps you could leave a little extra milk out for them, or if you're feeling generous add a small amount of cream to the milk before you put the saucer down.' He leaned forward and whispered again 'And you could leave some squares of red cloth around the house. If they disappear...' he leaned back and tapped a knotty finger against the side of his nose.
'Thank-you Doctor,' I said meekly, and got up.
'I'll give you two prescriptions,' he said, turning back to his scarred metal desk and pulling his presciption pad forwards to the edge of it. 'One is for two dozen fresh brownies, in case you find that yours are... somehow, shall we say, defective. And the other is for 200 valium tablets to help you relax somewhat.'
'Thank-you, Doctor,' I said with feeling, sitting back down while he wrote out my prescriptions. I'd been running low on valium all week, and had been extremely worried that the Doctor would refuse to renew my prescription. I left his office quite cheerfully a couple of minutes later with both prescriptions.
I was overworked, or at least I would be if I worried about the housework, but I didn't; I left that kind of worry to my sister. She had a doctor of her own, thankfully not Doctor Melchitt or even one associated with his practise, and I'd been careful never to mention to Doctor Melchitt that I had any kind of family at all. She fretted over the lack of brownies that we had, that she was unable to attract any, and that any she was prescribed seemed to just evaporate in less than a week. I'd sympathised with her, and told her that I suspected the house was simply ill-aspected and no self-respecting brownie would stay put for longer than a few days, but she was growing more and more resistant to the idea. So lately I'd been telling her that I'd seen goblin-spoor in the garden, which had triggered a mild anxiety attack that goblins might be hunting down her brownies and eating them.
Though goblins were indeed the most cannabalistic of the fey races the truth was somewhat more prosaic. I was crushing the valium that Doctor Melchitt had prescribed me and dissolving it in the milk that my sister put out for the brownies each night. Each morning I would find comatose brownies strewn around the kitchen, depending on where they were when the valium had kicked in. I gathered them up, inspected them and kept the ones that I didn't already have in my collection, and sold the rest on to other collectors. My collection was very nearly complete, I was missing only a mottled-red brownie that was typically only found in Hungary, and a large greenish coloured brownie that constantly oozed ichor and was normally only found near the seashores. Each of them were pinned down beneath large glass display plates with magnetised iron pins that stopped them using their fairy powers to escape. The collection was worth several hundred thousand pounds to the right person, and would land me in gaol for ten to fifteen years if discovered: ever since the fairy races were accorded the same rights as humans collecting them has been illegal.
Prescribing brownies wasn't illegal of course, as the prescription was just for chemicals that brownies found very attractive, and were regulated to stop collectors from using them to gather brownies up en masse. Every year it seemed another mass grave of brownies would be uncovered from the days when they were considered to be little more than helpful butterflies.
I was confident that with a prescription for two dozen brownies and 200 valium tablets that I could either ensnare the last two brownies I needed, or at least gathe enough of the other kinds to be able to trade for them. Then the collection would be complete, and I could start on goblins. I'd been planning this for a couple of months now, when it became obvious that I was nearly there on brownies. Goblins aren't protected by law, or by lore for that matter, even the fey races consider them to be vermin, so the collection would be legal this time, and I could exhibit it and take pride in it. I was getting quite excited by the idea. The downside would be that I would need to attract goblins, which would probably mean that my sister still wouldn't be able to keep any brownies for any length of time. I shrugged to myself, and wondered if goblins could be trained to do the housework.