Henderson is facing the prospect of a fine or a ban
Leading trainer Nicky Henderson will have a personal hearing with the British Horseracing Authority on Thursday over the Moonlit Path case.
Henderson was last week found guilty of breaching the rules of racing after the horse, who he trains for the Queen, failed a drugs test.
The 59-year-old had the right to request the personal hearing, which will be heard at 1600 BST.
He faces the prospect of either a heavy fine or a ban from the sport.
Last week, Henderson was found guilty of administering the prohibited anti-bleeding drug tranexamic acid to Moonlit Path before she finished sixth in a race at Huntingdon in February.
The Lambourn-based trainer had admitted three of the four charges he faced, but denied any wrongdoing in relation to the BHA's Rule 200, which governs administrating or attempting to administrate a positive substance.
He also insisted at that hearing that there had been no intention to enhance the horse's performance.
Moonlit Path was making her racecourse debut at Huntingdon and has since run three times.
The race was won by another Henderson-trained horse, Ravello Bay.

Sariska will be the filly to beat at Epsom Downs
Ante-post favourite Sariska heads 12 confirmations for Friday's Oaks at Epsom racecourse.
Michael Bell's filly heads the betting for the Classic following a superb display in the Musidora at York.
Last year's champion juvenile filly, Rainbow View, will be looking for a big improvement after finishing only fifth in the 1000 Guineas.
Henry Cecil is in search of a ninth win in the race with Midday, who won the Lingfield Oaks Trial on her last start.
She is likely to closely contest the Group One mile-and-a-half race having come second in the Blue Riband Trial against the colts at Epsom earlier in the season.

Ireland's representatives come in the form of Aidan O'Brien's Cheshire Oaks winner Perfect Truth and Jim Bolger's Oh Goodness Me.
Barry Hills' High Heeled, Clive Brittain's Nashmiah and Wadaat and Sir Michael Stoute's Phillipina are other contenders in with an outside chance.
Amanda Perrett's Tottie represents last year's winning owner, Julian Richmond-Watson, while The Miniver Rose and Three Moons complete the list.

Master Minded has won the last two Queen Mother Champion Chases
Odds-on favourite Master Minded endured a big scare before earning a narrow win in the Kerrygold Champion Chase.
The double Queen Mother Champion Chase winner was given a narrow lead after the last, but only because of a jumping error by eventual runner-up Big Zeb.
Barry Geraghty's mount recovered well and almost hauled in Master Minded, with Ruby Walsh on board, at the line.
However the 30-100 favourite clung on to win by a head to collect his fourth Grade One victory of the campaign.
Master Minded led all the way and the race appeared sewn up when Paul Nicholls' horse produced a big jump three from home to move four lengths clear.
But the Colm Murphy-trained Big Zeb reduced the six-year-old's lead and looked to have moved into a slight advantage before getting it all wrong at the last.
The mistake enabled Master Minded to move two lengths clear again but Big Zeb regrouped to produce a last-gasp charge before the finishing post came just in time for the English raider.
It was a fifth Grade One success in all for the French import, starting with the 2008 Queen Mother success.
He's won, and that is what it's all about
Master Minded's trainer Paul Nicholls
Winning trainer Nicholls felt that his horse had got "a little bit idle" during the race.
"Last year at Cheltenham he got a real fast-run race and I think he could probably do with a bit of company and a good gallop.
"It's the back-end of the season and I thought he looked as well as he's looked for a long time. But some of ours that have been in since last July have run a bit flat of late.
"He's won, and that is what it's all about," concluded Nicholls.
Big Zeb had failed to complete on his two most recent chasing starts, prior to a confidence-booster over timber at Fairyhouse a little over two weeks ago.
Geraghty said: "He's got his head down after the last, and was only beaten a head, so it was a great run - although it's disappointing to be beaten."
Trainer Murphy echoed Geraghty's sentiments, adding: "It's a pity to get so close and not quite get there.
"Our fellow is still on the up, and is still inexperienced, so we have something to look forward to next year."

JOHN SMITH'S GRAND NATIONAL, Aintree: Saturday 4 April, 1615 BST Coverage: Full TV coverage from Aintree on Thursday and Friday on BBC2 and online from 1345, and on Saturday from 1300. Saturday - radio coverage on BBC Radio 5 Live and live text commentary on BBC Sport website & mobiles

McCoy's 2008 National mount, Butler's Cabin, is entered once again
Tony McCoy will leave punters guessing until as late as possible over his chosen mount for the Grand National.
The 13-time champion jockey has made no secret of his desire to add this race to his catalogue of success and has the choice of four JP McManus-owned horses.
Butler's Cabin, a warm order in the betting for Saturday's big race, appears the most attractive option.
But McCoy fell from the nine-year-old 12 months ago and is thought to be considering a switch to L'Ami.
Butler's Cabin, trained by Jonjo O'Neill in Gloucestershire, was travelling superbly for McCoy before parting company with his jockey in an uncharacteristic fall at Becher's Brook on the second circuit.
He has been quietly campaigned in shorter handicaps this term and is priced at around 9-1 for the four-and-a-half miler.
606: DEBATE
I do hope McCoy rides Butler's Cabin as I have him ante-post but the longer Tony takes to announce his ride the more nervous I'm getting
shortheadwin
L'Ami, trained in Ireland and a 20-1 shot, has had a fine season but has a history of poor jumping and was another to fall in the 2008 National.
McManus' racing manager Frank Berry insists there is no rush for McCoy to decide which of the owner's four entries he will ride.
But it would be a big shock if he went for either Can't Buy Time (40-1) or Reveillez (100-1).
Berry said: "There is no pressure for Tony to make up his mind, because we have jockeys ready for the other horses. I'm sure he will wait to see what the ground is on Thursday morning.
"Butler's Cabin jumped well for a long way last year and has come back and run a good race in the Kim Muir at Cheltenham.
"He's a bit higher in the weights this year but he has come out of his last race well - and you would have to be pleased with him."
He jumps fences the best way for a National horse, he's not extravagant and is quite a clever horse
Brooklyn Brownie's trainer Malcolm Jefferson
L'Ami made it only as far as the second fence 12 months ago, ending the riding career of Mick Fitzgerald with a crashing fall.
Berry said of the 10-year-old gelding: "He's been round the cross-country courses a few times since and he has got sharper at it. He's fit and well, so I hope he will run a good race."
Meanwhile, Malcolm Jefferson believes Brooklyn Brownie (33-1) could go well, having finished second over the giant fences in the Grand Sefton back in November.
The trainer said: "I just thought we'd give him a run over the National fences, because he's always had the appetite to jump. He ran well to finish second, and I said to his owners then if everything went right we would aim for the National - and that's what we've done.
"He jumps fences probably the best way for a National horse, because he's not over extravagant and he is quite a clever horse. Over four-and-a-half miles, you never know - but he ticks a few boxes."
Clerk of the course Andrew Tulloch said conditions on the Grand National course were expected to be good, good to soft in places. He said: "We are forecast to receive some rain on Friday night which is either going to be 1-2mm or 4-5mm depending on who you listen to.
"It has been a dry week, and there isn't any sign of rain coming before Friday, so we will continue to selectively water the Mildmay and Hurdle courses where needed."
The official going for the Mildmay and Hurdle courses is good.